Ive never had a 28-32 day cycle. It was more 32-36 days. Well back in April I had gone farther than 36 days without a period. After a week and a half or so I started. Well I haven't had a period since. Ive missed two periods and I have no idea why. I went to the doctor yesterday and they tested me for pregnancy but it came out negative. They told me if I miss one more period then I need to come back and they will do blood work and if they don't find anything I will need an MRI and again if they don't find anything I will need a pelvic ultrasound. The past two months I did not stress. Now I am a little nervous. I'm 17 years old, I don't want to be infertile. Not that I want children now either it's just I know I do in the future. Please help :/