Hi In_Flux~
Although I have not been in your current situation, I have a friend that was. I was the person that befriended him actually. Anywho, he was with his girlfriend for 3 years and they broke up. He was feeling lonely, and joined a class that I was taking also. He joined a class that interested him, as a result he would meet people with at least one thing in common to base a friendship on. Maybe you could try that. And if it does not work, at least you might get something from the class. Best of Luck!