Hi, im a 15 year old girl and have had my period for three years, but I'm getting kinda worried I haven't had my period in two months and I don't know what's wrong, i don't think i can be pregnant considering I havent had sex for six months?

I suggest you talk with your doctor.  Information you get online is a starting place for your conversation.  It can't replace a checkup!

Here's a site with several possibilities listed.

http://www.womenshealthmag.com/health/late-period

I wish you good health, and a positive outcome to your doctor visit.  ❤️