Hi, I'm a new member and I know just how you feel. I've spent a long time thinking that I was just the most useless, worthless person on the planet and really got to aplace where I couldn't drag myself to do anything or even do anything to cheer myself up. 8 months ago my doctor started me on some meds which seemed to work really quickly but then wore off. We've fiddled with doses and now I feel more stable, at least stable enough to start trying to do something about it. So, perhaps you need to speak to your doctor about your med's, you probably should get some therapists help as well if you can. Meantime I hope knowing that there are others who feel or have felt like that help.
Take care,