I’m posting because I’ve recently realized some behaviors within myself that would suggest some sort of underlying problem or mental illness.

So for some background, I’m a 20 year old male and just finished my semester of college. I’m driven, ambitious and like to get stuff done. I’m working on starting a business, I’m in an awesome sales job, and I’m planning on going to law school. I love to read and learn. I’m also confident in social situations and have no problem talking with people. I also do my best to maintain moral, Christian values.
HOWEVER
In the past, I had really bad depression. From ages 14 through 18 I always felt depressed and unmotivated, and found solace through unhealthy relationships with girls I met online, self-harm, and with alcohol. I went through several relationships where I was cheated on and manipulated, and I’m sure, though it was subconscious, that I did my own fair share of manipulation. The primary source of depression was feeling alone, although it was also sometimes random and unconditional.

By the time I turned 19 I had virtually overcome depression. I ended up going on a mission trip for my church and during that time period I didn’t date anybody, learned how to be happy alone, developed self-confidence, and obtained reasonable stress/ anxiety tolerance. It was very transformative.

I just finished my first semester at college. During that time, I got into a healthy relationship, was working on building my business, and got pretty good grades. However, as the semester progressed, I became more overwhelmed and found myself under heavy stress levels. I got a lot of anxiety, but I still managed to maintain my schedule pretty well. Adding to the stress, I could see that my girlfriend and I were starting to go different directions in life and I knew we’d break up with her eventually.

Then with like a week left in the semester, I cracked and did something stupid. I ended up creating a fake Snapchat and messaging my girlfriend with it to test her loyalty. I had no reason to question it, although in the past I’ve been cheated on and my dad also cheated on and left my mom. At this time, my ambitious drive also failed and I put in basically the bare minimum effort that my life allowed. My girlfriend and I broke up, and after that, I even felt tempted to go back to alcohol for a day or so, although I didn’t.

That served as a wakeup call so I shaped up and recovered pretty quickly (as far as being able to start working hard, studying, etc. I still feel pretty sad as far as the breakup goes, but I’m not planning anything stupid) and resumed my schedule studying and working. But I still feel concerned at the behavior I exhibited when I cracked. Because even if I only crack occasionally, it will still be dangerous and disadvantageous to my life and relationships.

I feel like there are 2 contributing factors to my breakdown:
1. Suppression. I feel like I was suppressing my stress rather than working through it. That allowed it to accumulate internally. I feel like one of the ways that I learned to deal with stress is to avoid it. Like I didn’t even cry when my parents got divorced when I was 19, although I did still feel sad and worry about it. So it’s possible that sometimes I suppress emotions rather than working through them all the way.
2. Failure to cope. My ambitious goals (it’s also worth noting that sometimes perfectionism and overly high goals contribute to my stress) caused me to devote all my time to being busy. I never took time to chill with my outlets, such as playing the piano, praying with quality, composing music, or writing in my journal.

So what I’m wondering is
1. Is my self-evaluation in the previous paragraph correct and complete? If incomplete, what other underlying mental processes or illnesses would cause me to crack and act out like that?
2. What can I do to stabilize myself and avoid occasional rash decisions in the future? Is it as simple as not suppressing my thoughts and taking time to cope?