This advice helped me a lot when I had a lot of depression in my younger years.
We have a natural tendency to believe that if we felt better, we'd be happier and if we were happier we'd do more things. That is backwards.
First you must do more things. Then you will have new things to think about. This will make you feel happier and then you will feel better.
Schizo-affective disorder is probably the worst thing. I'm sorry you have to deal with it. A decent diet and exercise will probably help a lot.
Female, 5'3", 50, Starting weight: 163lbs. Current weight: 135 (more or less).
I can squat 187.5lbs, press 75lbs and deadlift 200lbs