I may be pregnant??

Soo i had unprotected sex with my boyfriend February 13th (not planned, mind you), and my period ended just a few days before that. Just in this past week, I've started to see a lot of symptoms of pregnancy (headaches, intense nausea, light pink discharge/spotting a couple of times, etc), and I took a test before I was supposed to get my period on the 8th, but it was negative. My mother told me to wait a week after I'm supposed to get my period and then retest (her pregnancy tests were all negative the first month as well). I'm stressing out. I still haven't gotten my period. Could I still be pregnant?