I think maybe an onion would help...
Sorry to hear that, I hate feel emotionless. I like to cry too. I never really cried a lot, I can't be sad for many time, and I hate it. I try to think in the bad things in my life, but just think doesn't help me to cry, I have to imagine that I'm talking to someone or talking to someone about it. I don't know if it would help you, since sad things don't help. Feeling rejected help me crying to, but yes, I think this are maybe autodestrutive things to try out.
Well, my experience with zoloft didn't changed my crying habits, but it appears that it did to other people.