Just need to rant

I'm in a slump after ttc for just over 3 years now I have kept faith and hoped that every month would be my turn to be a mommy. Well this morning I just found out another one of our friends is now expecting and I want to be so happy for them but I just can't, I'm miserable, I don't want to see anyone that has a child or is pregnant that is close to me. I don't understand why it has been so difficult and I'm thankful that my doctor is nice and trying to help us but I've had enough I just don't know what to do. How have you ladies dealt with feelings like this?