Re: what 2 do when..
Re invent yourself, take a long hard look at what's negative in your life, give them up, take a long time out to do this and come back fresher and stronger.
Giving up isn't bad, we all leave this world at some point, no one lives forever. But its better you fix the wrongs, help others and make your life mean something worthwhile and gain that sense of self worth again by helping those less fortunate.
Remember, if you can't live for yourself, then live for others, make their lives better. It's a fulfilling and satsifying way of life.
Good luck.