Vaginal Discharge

Okay, i need help. So i’ve had my period since i was 12, i am now about to be 19 & have never dealt with or seen this coming out of me before. i have brown discharge, dark brown. my period was suppose to start today, but instead i started discharging this brown stuff. my periods are always EXTREMELY heavy like i have to change my tampon every 3 hours maybe even more frequently kinda heavy & this is just like a little bit like i put it a tampon thinking it maybe was my period getting started but it only was on like the 1/4 of the tip of the tampon. me & my boyfriend had sex about 2 weeks ago before he left back to his hometown, he didn’t cum or anything down there, but we did not use a condom and i’m not on any type of birth control so idk if this brown discharge is a sign of pregnancy i would just like advice. normally i know when my period is coming bc i can feel the cramps about a day before but so far its been two days of this dark brown discharge light flow so if anyone knows pls help