Maggie,
I agree with others who said that just making sure you aren't bipolar might be a good idea. Even if you are though, some of what you describe is easy to relate to. I'm not bipolar but I tend to be very highly motivated and especially before my diagnosis with CF last year, would pile on the activities til my schedule was booked. I'd get exhausted and of course, sick. Then I'd feel frustrated and like a failure. In some areas where I have talents it was hard because I was being encouraged by bosses, teachers, etc to succeed - but in doing so worked harder than was wise with my CF health. When I didn't feel well I couldn't do as much, didn't stay as stimulated and didn't feel happy, so I got depressed. Having a chronic illness can be a bit isolating, so reaching out to your old friends, family, Cfers here and any other sources of support and companionship might help a little.
I think finding balance is very important. There are so many interesting things to do in this world, but we have a limited time to do them so we have to pick and choose. I hope you get better meds and a good therapist to help you.