Can’t get pregnant?

Now I’m seriously feeling crazy that I cannot get pregnant at all. I been trying and I always end up getting my period. This month I had a 37 day cycle when I thought my period wasn’t coming but it ended up showing up anyways... but 7 days later. Is it possible to have a 37 day cycle or is there something wrong? Anybody can give me any information it would be helpful because I’m starting to feel sad every time I get my period.