Brown "bleeding"

AF was due last Thursday. I spotted light pink for one wipe, then nothing. Same Friday. Started getting thicker BROWN "blood" off and on Saturday and Sunday. Today is not so thick off and on brown/dark red. I've been throwing up since Friday. Anybody experienced this and end up pregnant? I've taken a test and it was negative. I had sex 2 1/2 weeks ago so wouldn't it be too early anyway?