Issues with Previous Job

I recently resigned from my previous job, where I had been for two years, to go back to studying but there had been several issues during my time there and lingering issues (mostly me overthinking) that just won't let me move on. Sorry, this might be quite long.

1. Main issue - my old boss.
My first day on the job, my boss walked into the office and sat down without a hello, no welcome to the team or anything that should have made me feel more comfortable and welcomed on my first day. The job slowly became unbearable at times due to the attitude and demands of the boss, not to mention the boss was incredibly unapproachable and intimidating. I received no structured training and, in fact, very little training from the boss despite having no previous experience but I surprisingly enjoyed the job. It was the boss that ruined it for me. I was made to feel like things were my fault when actually the things I had been stressed about and 'blamed' for were actually not within anyone's control and couldn't be helped or prevented. I had no sense of what was important and what wasn't, so often felt a huge amount of responsibility was on me for many things that I shouldn't have been. I was also given all the work the boss didn't want to do, which I was ok with as I was training and that was to be expected but I was also trained incorrectly or told the wrong information because the boss didn't know how to or have the answers but would never admit it. I learned most of what I knew from another colleague (we were a small team of three but unfortunately never felt like a team). The boss seems to be defensive towards anything and anyone, making work politics difficult and the whole office was aware that the toxic work environment was often a result of the boss.

2. The relationship breakdown between the boss and colleagues.
This is really where the main problem started. I felt piggy in the middle a lot of the time as the issue was between my boss and the other colleague in our team and not with myself. Due to the behaviour and attitude of the boss, we had complained to someone with more authority to try and have the issues resolved - it would be a disaster to have aired these issues with the boss directly. The boss had frequently belittled my colleague in front of me and vice versa, called my colleague out on things because they weren't done the way the boss wanted (but the end result was the same), and always saying my colleague was wrong even when they weren't. In the end, my colleague had gotten HR involved and it didn't end well for them. They left for another job on bad terms, leaving the team with just myself and the boss. I was dragged into it indirectly and HR tried to turn me against my colleague. It doesn't help that HR is friends with the boss.As soon as my colleague left, the issue was swept under the carpet and the boss continued to blame others for their mistakes and took no responsibility, ever.
There were other colleagues who had experienced difficulties with the boss, however, they were not part of our team so it would only be a small issue for these colleagues. For us it was constant.

3. My relationship with the boss.
I got on well with the boss when they were in a good mood, but they were often very condescending and often felt the need to assert their power and authority on others, including me, because they felt that no one took their position within the company seriously. I sat in the same room as the boss and would often feel like I had to be careful each day because the boss was always in a bad mood, being rude to clients and colleagues and leaving me to deal with tasks that someone in their position should have really been dealing with. Any little thing could set them off and I felt physical dread. They also got stressed out about little things very easily which would mean a bad mood for the rest of the day. I felt out of my depth many times but received little help when I needed it, particularly after my other colleague was no longer there. I often stayed late voluntarily to meet deadlines but received little thanks and any praise received never felt genuine. I just tried to get my head down and was always nice and polite to the boss, but vented to other colleagues on days when it was particularly tough as everyone knew what the boss was like even if they weren't in the team. It wasn't worth speaking to the boss about how I was feeling as I often felt like everything was a game to them, manipulating people and things to work out the way they wanted for their own gain but coming across as sweetness and light to people who mattered but near the end of my time there, tried to keep me on side and tried to treat me like a friend all of a sudden. I just kept telling myself only 8 months to go before going back to studying etc. It put a strain on my life outside work, including with my partner who had to hear of my bad day everyday for two years. Other family members also had to deal with my constant complaining.

4. My issues now that I'm gone
It has only been two weeks but I even feel lost without the job, very much with Stockholm Syndrome. I was miserable when I was there and couldn't wait to leave, yet it doesn't feel right not being there anymore.
I have been encouraged to apply for another position within the company which my studies would help qualify me to do but after the experiences there, I don't want to even if this was perhaps the only opportunity I could get to have my dream job.
My boss deleted me off Facebook today (nearly two weeks after my last day) which shouldn't have bothered me at all but it did. I did most of the work for the boss, tasks that I shouldn't have been doing and I went above and beyond to please so I feel offended that they would do this. They did seem to have issue with the fact that I still met up with my other colleague though, but it was never about picking sides. I have a feeling colleagues who are still there had maybe said some of the things I had said behind the bosses back. I don't mind, I was never nasty or malicious. I just spoke the truth about the situation and how frustrated and unhappy I often was.

A lot happened in the two years, but I don't want to write every single thing out. I hope what I have shared makes sense. I can't seem to let go, even though it was a horrible time and I don't know what to do. I feel like I've gone from not having much free time, to having too much free time and can't seem to relax or transition properly. Maybe I just need to let time heal me

It's only been two weeks so if I were you I would give it some time. Toxic work environments are not easy to handle and they do tend to stick with you afterwards. I've been there.

Making this post is a start at healing, so kudos to you. I'm going to point something out that is a personal preference of mine. I never facebook friend a person I work with. I have several facebook friends that I've worked with in the past, but never current co-workers. I know several people who do the same thing. I also do not indicate my place of employment on my facebook profile.

Good luck with your educational pursuits!