HELP PLEASE!

Ok so... I'm literally so confused right now... I had my period about a week or so ago.. but it lasted only about 3 days and it usually lasts 5. It wasn't quite a normal period for me I guess.. but it also didn't exactly come on time either. It was late by a week. Anyhow, I'd also had unprotected sex and thought I was pregnant but when it showed up I figured ah ok nevermind.. So, now, I noticed some pink on the toilet paper so I guess that's spotting, right? And I'm having some cramping... Am I about to get my period again?? It's not supposed to come for another 10 days or so! Has anyone ever experienced this? I'm going to post in one of the pregnancy forms too but is it my period? pregnancy? or an STD? I'm scared I may have contracted something HELP!!!