Period or pregnancy

So I had unprotected sex when I was ovulating, and my partner ejaculated right outside my vaginal area, but not inside. I am not on any form of birth control and he did mention that when he withdrew it was a very close one. Regardless, I started feeling a little funny a week after. My nipples became very very sore, I became exhausted, started cramping and was slightly nauseous. Well my period due date varies by 4 days, but the longest my cycle ever went was to the end of those 4 days. It usually comes on the first of those days which is cycle day 33, versus cycle day 37. Well I got it on cycle day 38, thinking I wasn't going to get it at all. I started spotting on cd 37. So I was relieved that I wasn't pregnant. But now i am on the second day of my period and it seems as if it's already going away. It defiantly wasn't spotting, but it wasn't my full-blown period that I usually get at all. It was still red and what was alarming is I had a lot more small clots than usual. Mine are usually black though and most of these are pink-ish clots in red blood. But in two days I only filled up one tampon, the rest only being like a quarter full. I mean I doubt I'm pregnant since I'm bleeding with clots and some cramping (which not to mention, I didn't cramp nearly as bad this time as I normally do). Should I take a test anyway just to double check, or should I go to my doctor?? And what are the actual chances that I could be pregnant? I don't know what to do, I just want to make sure everything is okay and this is all defiantly out of the norm for me.