Sooo i cried today

I have been trying for a baby now for 10mths..we are now trying again. my sister is 11 yrs younger than me and has informed me she maybe pregnant and is going to dr tomorrow for blood tests. It just made me sad everyone around me is having good luck and im not having any luck at all. I work in a dr office and get 16yr olds in that pregnant and im 31 and still haven't yet. Anyone else feel jealous at times?