I think I'm pregnant?

I had sex unprotected on a fertile day. I was 2 days late before i noticed a spot of brown blood on my pad , then the next day only when I wiped I saw pink blood, nothing on the pad, the day after that the same thing, but when I put a tissue up my vagina it is bright red with dark lil clots it seems, now the 3rd day the blood is starting to come on to the pad but not as heavy as my normal period , it doesn't fill the pad like my normal heavy flow but I'm starting to see a lil more dark lil clots. The flow isn't increasing nor is the cramps. I always had a heavy flow & bad cramps for 6 years. Could I be pregnant . Cause my period stopped after this 3rd day when I usually last a week