Since i started my periods when i was 11 they have never came on time. I could go between 2-4 months without them. It is also hard for me to lose weight, been on diets but nothing seems to work. I went to the dcotors and said to them, then i got an appointment to go for a scan to see if i have pcos, they said that everything looked normal. This was about 6 months and that was the last time i had a period. Also i was with my ex boyfriend for over 2 years and we didnt use protection but i never ended up pregnant. Do any off you know what else this could be?