Haven't had period in 2 months help?!!!!!!!!!!!

I just got off BC 4 months ago have had pretty much a period every month up till last month I didn't have a period at all last month or this month yet! Pregnany test negative ! I had this problem with periods for awhile now got on BC to fix it and had got off to ttc. Idk what's the problem of me not having a period at all within the past two months and had this problem before . What would be the problem or what could I be put on to help me ttc with this problem of not having a period?!!! Help plz anybody else had this problem?!!