Read a book for pleasure. Nothing to do with relationships, just for the pure pleasure of it.
Get a laugh a day. Tune into a comedy station, read the comics. Take 5 minutes to find something funny in life.
Find a challenge - crosswords, a musical instrument, a foreign language.
Help others - volunteer to do something for the needy.
You have to get yourself back on track. It will take time but you can do it, just as many others have done before. You CAN do it. You will need help and it will take effort but you CAN do it.