I had sex this past weekend and we did it about 3 times. After one of those times i cleaned my self off and noticed a brownish color like old blood...I do skip my periods every other month as per a discussion with my gyno and she said it was fine. I still take the pills regularly and its rare that i miss a pill if I do I do not have sex for a few days minimal. What could be the cause for this brown discharge that I saw that once and havent seen since?