help!

So I had my period 2 weeks ago & bf and I have been having unprotected sex .. before my period we had sex when I thought I was ovulating but still had a period.. very short tho only 3 days .. usually it's around 5-6 but it seems like a mild period.. now I feel nauseous, tired, extreme soreness in my boobs & dizzyness sometimes. I took a pregnancy test a couple days ago and it was negative but I guess it would be too early to tell?? Has anyone had there period while they were pregnant? And was it a normal period?? I feel awful someone please tell me I'm just pregnant.