Please answer! Kind of gruesome but I need help...?

About a week or maybe a little less ago my boyfriend and I were messing around and eventually it got into him penetrating me for about 5 seconds. He definitely did not ejaculate (he jacked himself off to do that a few minutes later when we were done). There might of been a very small amount of pc inserted but not positive. I'm due to get my period in about a week, and when I woke up this morning I found a small amount of brownish discharge in my underwear that had dried by the time I had awaken. Does this mean I'm pregnant or what else could this mean? Thank you!