Birth control and antibiotic help!

I was diagnosed with strep throat... I was given antibiotics, a 1 dose steroid drink, and a pain shot. I also take Birth control. Not to prevent pregnancy as I have had my tubes tied but for painful cycles, and to help regulate my cycle.... The 3rd day I was coughing and felt a gush. So of course I'm thinking crap I wet myself I was coughing so hard. Went to the bathroom and it was blood. I have 2 days of antibiotics left. I'm still bleeding. My question is is this normal and once I complete the antibiotics will it stop??? Oh and I'm guessing my actual cycle will also be off???