i had unprotected sex on the 17, 30, and 31.

im 16 and have VERY regular periods. my last period stared on the 11th of december ended on the 16th, 17th. im typically 30 days never really off. maybe a day give or take.. on friday the 2nd, i had very very light pink spotting/bleeding. on the evening of the third (about 10pm) i started to really bleed (one super tampon a day) typically i will go through about three a day. and one pad. i havent used a pad at all and its less then normal. i did a test and it was negative, but im not due for my period till the 12th. idk if im just over freaked if i could be pregnant or if my period just came early?