Redhead's given you the best answer, you've got to put yourself out there (force yourself if need be) otherwise you can fall into the realm of self fulfilling prophecies.
My ex walked out on me several years ago around this time of year (it was tough, not my fault, her racist family) but I had to pick myself up dust myself down and start all over again.
It's not easy I've suffered a variety of setbacks since, but I stuck at it and won through in the end.
To love someone you have to be willing to accept you may end up making a fool of yourself that's why it gets harder as you get older, life has a terrible tendency to corrupt one (if you allow it).
Make some new years resolutions along the lines of 1 No more unfair compromises. 2 Do things you enjoy.
Try getting involved with the local non-league football team or a charity, and above all else remember she may have suffered similar setbacks to yourself (but don't allow that to become an excuse for unreasonable behaviour), just relax, be patient and keep working at it eventually things will turn around. Nothing worthwhile in life is ever easy.