Bloody Discharge?

Well I just noticed that I had blood in my underwear. I just finished my period last Thursday so I know it's not that. I went to the bathroom at around 12:30 and there was nothing, but I did feel a sharp pain right before then. It's not a lot, but it is a mix of both red and brown . I don't know what it could be. Has anyone experienced this before or might know what it could be?