So I had sex on February 7th. The guy stuck his penis inside me for a literally less than 30 seconds then put on a condom... (i know he's an idiot). Anyway, I got my period that month on the 12th, 3 days early but I'm irregular, and it pretty much followed the normal heavy flow of four days. I then took a pregnancy test on the 28th and it came out negative. However, for the past couple of weeks my stomach has looked slightly bigger, my vaginal discharge has changed to this thick yellowish discharge, I've been getting headaches more often along with a stuffy nose, and my nipples have slightly grown along with my right breast. Could this be PMS symptoms or pregnancy?