please help!

I was on antibiotics while taking my bc pill... I have used conforms ever since I was taking the antibiotic, and still am using them. I stopped taking them about 2.5 weeks ago, since then I’ve had brownish discharge and sometimes a little blood. This week my stomach has felt so full and achey and uncomfortable , and sometimes some nausea with it. Is this the antibiotics and getting back to normal with my pills?? Or?