I am 20 years old and haven't had my period in 8 months.

I have always been irregular but since I was about 16, my doctor put me on birth control to regulate my period. I was on it for a year and had my period then. After i stopped taking them, I didn't have my period again for a year and a half and went back on it when I was 18. Went on it for about a year or so, then got off it 8 months ago.

If i am not on birth control, I dont see any signs of my period.

What could it be? it is making me worried! though i am young, I want to see what I can do before it is too late.