HELP ASAP!!!!!!

Okay guys. I had sex almost 2 months ago with someone that cum in me, I had a period the next month after we had sex, that period was normal.well this month i took a test last weekend because I was a day late on my period and it was negative. Well I am now 8 days late on my period and have no clue what is going on. I am terrified... please HELP!!!!!!