I take a BC that only gives me a period once every three months. I had one last week September 26 to the 28 or 29. I missed three pills last week.. I had unprotected sex Thursday night. Today I woke up feeling different and my back and belly aching. When I pee there's a drop of blood in the toilet and some when I wipe but none on the pad. I'm worried because this isn't what my periods are like and I shouldn't even be having another period. Can you help me?