I had unprotected sex 4 days ago. my period isn't due for another 5 days. but i think i could be spotting. took a pregnancy test today came back neg.

Too early: It's too early to know, and spotting unlikely to be related. However, you are playing russian roulette by having unprotected intercourse. You are at risk for pregnancy and stds. If you develop symptoms of vaginal discharge, pelvic pain, spotting that's not your period, or fever, you might have an std and you'll need checked. Wait until your period is late before doing a pregnancy test. Be well.