Tons of good advice...and all of it from the heart...
I've been there twice, and the one thing that helped me more than anything was getting out and doing what I loved. The only thing I might add would be take time off from relationships, don't get caught in any rebound situation, (does not necessarily mean don't date, just don't get serious for awhile). I took several years and when I was finaly comfortable with myself and living alone, doing what I enjoyed doing with my group of friends, everything else fell into place and I am happier now than I have ever been in my life!
There is a light at the end of the tunnel, sometimes its just hard to see...But it is there