I'm pretty happy with the way I've spent my life, so if it had to end then I wouldn't have too many regrets. On the other hand I still feel like I have a lot of things to do and see which is surely normal for someone my age - it's not feasible to have achieved everything I want so soon. Guess that's what makes life worth it for me, always working towards something...without that I'd imagine life seeming pointless and unfulfilling.
I can't really understand young people who would decide to end it all. I know it's a cliche but it is an easy way out. I'd rather beg, borrow and steal, do the things I'd always dreamed of, fly off to some far away land and make a second life that would maybe make me happier. If you're really that unhappy and had nothing to lose then there's no risk in doing something extreme like that.
I kind of understand the OP's talk of living in limbo, but is that not something you can change? I do believe variety is the spice of life, and having a good work balance definitely helps keep me content. How many people on their death bed say "I wish I'd spent more time at work" ?
I don't pretend to know the OP's circumstances but it reminds me of Stephen Fry (who's episodes I'm sure you're all aware of) saying something along the lines of "I don't want to die, I just wouldn't mind being dead". That to me suggests you need to force some changes.