I've felt this way before...like all the major decisions in my life had been made and there was nothing left for me to do except move on to the end. I was WRONG!!!
My advice is give yourself a deadline for wallowing in self-pity (and that's what it is, at least in retrospect) and then start doing SOMETHING. Help someone, learn a new skill; anything that gets you up, moving and hopefully in a different environment if only for a short time each week.
There were several books that were extremely helpful to me during my darkest days. When I get home I'll post them.
One good thing, the fact that you've posted here looking for help indicates that you recognize something is wrong, even if you're unsure of the next step. That's a positive sign, and it's mostly downhill from here. Trust me on this.