I also had a hard time re-adjusting to working part-time. I now work every weekday, though not for a full 8 hours, and I have been managing pretty well in this job for the past few years.

What helped me is coming up with little rituals to look forward to at different parts of the work day. The night before work, I drink Lipton decaffeinated honey lemon green tea. The warm, soothing tea helps me get to sleep--it also contains chamomile, which helps slow my thoughts and ease me into sleep. I sometimes have multiple cups since it's decaffeinated and has no calories (though I do sometimes add sugar, which of course has calories, but has never kept me awake personally--though it could be different for you). In the morning, I get up an hour before I need to and do gentle stretching and reading--anything I find relaxing. It's hard to wake up early if I've had a restless night, but in a sense it's also easier to get out of bed when I know that I will be doing something I enjoy for the first hour to ease into the day. I actually have a harder time when I sleep later, but have to jump straight out of bed and rush to get ready. During the workday, I bring my smartphone and read inspirational emails. You could also bring a book you like and read a little bit on break, or even bring a journal and write down your worries if you have a private place to keep it. At the end of the day, do something to reward yourself for making it through--anything you consider a treat. I hate painting my nails because I always do a bad job, but a lot of people find it rewarding and feel pretty afterwards. You could also take a bubble bath or go for a walk on a pretty trail if the weather is decent--though of course you might want to take a buddy for safety.

Above all, be patient with yourself! It took me a long time to ease back into working, and I had a couple of unsuccessful attempts when I tried to go back into the field that I had studied before I became ill. I ended up having to find much less stressful work, but I enjoy it much more and hope to soon be off of disability, as I'm making close to the cut-off. I was very frustrated by the initial setbacks and was devastated when I couldn't do my first two jobs, but I'm very happy with where I'm at now, even if I sometimes get mad at myself for not living up to my pre-illness potential.

I'm rambling, haha, but on a side note, we have similar diagnoses (mine are SZA (Bipolar type), PTSD, generalized anxiety disorder, and insomnia), so feel free to shoot me a message if I can be of any help Best wishes! You'll do wonderfully--remember, returning to work is a process, not something that becomes easy overnight--so be patient with yourself!