Kinda confused

Sara
So in the past month I've had had sex 4+ times and it's my first day on my "period" however it is just brown discharge with a hint of blood.. Usually it is very heavy I'm on  an oral contraceptive and we used condoms so I don't think I could be pregnant however it is quite odd, and I've had morning sickness in the past couple days 
I also have all the signs etc acne terrible cramps mood swings just kinda nothing is happening down there