Why when everything is going good I feel like crap

I have Bipolar 1, ADHD, and Anxiety. They are on a regular basis fairly well managed, and I am medicated for all of it. In the past I've had major financial issues that have leveled themselves out now that I have filed for bankruptcy and are debt free besides student and car loans. My job was also toxic and I got a promotion to a much better job in a different department in the last three months The only other primary trigger I have I loneliness, I have no close friends. I have coworkers I'm friendly with, and my family but that is about it. My family is disfunctional but my parents love and support me.

In the last month I have found myself going back into a depressive state, sleeping more but still feeling tired and sad most the time. Why is it when suddenly things are going so well that i feel like such shit?