If it's somebody you only communicate with on Facebook, then honestly it's not probably a true friendship. I am concerned that someone who makes comments on your posts online and isn't really real life friend is your "window to the world". I'd address it with a therapist.

Facebook seems give causing people tons of aggravation. Also you might want to try looking for male friends. It seems that looking for women friends especially all very young ones causes more problems than it's worth.