Feeaking out..

Alicia
So yesteday I started having brown discharge but very very little. It was only there when I wiped. This morning I woke up and there was more. Like I'm on my period. I know it couls be just old blood but my period wasn't supposed to come for at least another week or two. And I really feel like its not my period because there are absolutely no symptoms at all. I can usually feel it. I eat a lot the week before. I start to get cramps on the minute I'm on my period I have killer cramps. I had unprotected sex about 14 days ago. Can it be anything?