I keep going for my girls because I know they need me. If I didn't have them, I'd be likely to crawl in a corner and not come out for a few days - or weeks - or months.
I also have the hope of Christ to keep me going. I know that eventually I'll die and none of the bad stuff that happened to me on this earth will matter, anyway. All that will matter is what I did for Him while I was still alive. Some days I just don't "feel" it, though. But feelings are not faith.
Sorry. I don't mean to preach. You asked how I pick myself up, and that's just my honest answer (which will probably be voted down because I mentioned Christ). I have to look outside myself because if I don't, I won't see any reason to continue with anything.