Possible to bleed like a period but be pregnant?

Ok so my periods usually last about 5-6 days and are pretty heavy. My boyfriend an I had unprotected sex 2 weeks after my period had started which I understand is around when I should be ovulating. We had sex 2 days in a row. A couple days to a week later I started getting minor cramps like mestrual cramps just NOT as bad as well as wanting to eat like ALL the time. I've also been VERY gassy lol and peeing a little more than normal. However about 10 days after we had sex and about 5 or 6 days before I was due for my period I started spotting but then it turned into a pretty heavy flow but only last 4 days instead of 5-6 and turned into some light brown spotting when I wiped. Normally my periods start off very light and don't get heavier tntil about the 2nd or 3rd day in. I don't notice cramping tntil about the 2nd or 3rd day as well. This time my cramps kicked in BAD the 1st day just like a menstrual cycle and STARTED off heavy and got lighter towards the end. Basically it was backwards from normal. I'm NEVER that early. And I NEVER cramp before my period. Is pregnancy even possible? I'm so confused :/