worried i could be pregnant

hi, so i’m 17 y/o and i had unprotected sex with boyfriend two weeks ago. he never ejaculated and he hadn’t ejaculated anytime beforehand. however, i’m due for my period and i’m getting cramps but very little bleeding. the discharge was at first a light brown, and then later in the day it was a much darker brown. so i took a ClearBlue test which came back negative. i’m still scared because of my body’s irregularity, please help if you can! i’ve been having panic attacks and haven’t been able to sleep