spotting

Kelly
So today I woke up this morning and there was a little blood on my undies. I brushed it off, changed and went to work. Hours later I come home use the bathroom and there is even more blood on my undies! Dark brown blood. I'm on birth control and I'm not supposed to get my period for another 5 days. This also happned last month as well with the spotting. I've been on birthctrol for 5 years, why all of a sudden? Help!