I feel so guilty

When we started trying for a baby I knew it wasn’t going to be easy. But I never expected it to be so damn hard. I try to be optimistic, but is really hard to stay optimistic when everywhere I look my friend and family are getting pregnant on accident. I can’t stop myself from feeling angry or jealous, I mean how come people who didn’t even want a baby are blessed with one so easily. I always end up feeling guilty, for not being happy for them. Does this happen to anybody else?