What Causes Brown Discharges Mid Cycle?

I am 18 and have been on Seasonique since I was 16. I am good about consistently taking my pill every morning. I am 5'9" and 150 pounds. My boyfriend and I have unprotected sex every once in awhile since I am on birth control, but he pulls out also just to try and minimize the chances. For the past week or so I have had clumpy brown discharge. I am not supposed to get my period for another month and this is not the first occurence. It really bothers me and is really annoying for me and boyfriend. Is there anything i can do to make it stop?