2 possible opitions.
If you had sex unprotected, sperm can stay in your system for up to 3 days, so that white sperm combined with a little bit of bleeding,(since you were almost done with your period) would turn a pinkish discharge. You might not be pregnant.
Or, maybe it is implantation
discharge,but really, I've never heard of that.
I say just take it easy, wait until your next period due date, so you wont have to waist ur money on pregnancy
test. If your period is late, THEN buy a pregnancy test.
I hope this helps and good luck!