The pain in TTC

My man and I have been trying for a baby for two years. I swear everyone around us keeps getting pregnant, in the mean time (anyone else experiencing this phenomenon?). We just got another call that my sister in law is expecting and I just broke into tears. They always joked that I should get pregnant and do the baby carrying so they didn't have to. I feel disgusting for being so sad/jealous but this is the 4th pregnancy in the family since we have been trying, it never feels fair!