I was recently prescribed a 2-pill/one-night dose of azithromycin as a precautionary measure prior to having a water sonogram done on my uterus. the dosage of Rx was 500 mg per tab and instructions were to take both at once for only one night. That does made me feel very ill- nauseated, bowel movements, abdominal discomfort, and even a little dizzy (on/off). The nausea lasted hours. The next morning I was able to go to work, but still felt a bit of abdominal discomfort; felt slightly out of it the whole day. It is now 4 days since that dose and I am experiencing loose stools, the urge to go often (even if not needed), and most frighteningly I now see a bit of bright red blood on the toilet tissue, had one blood clot-like stool (small), mucous on tissue (mostly clear), and notice a fishy odor from the toilet/tissue. Is this likely from that medicine? I've never had these issues ever before. I am also recently on birth control (from the same doctor and in preparation for an IVF cycle to start at the end of the month). Looking for some insight into what caused this and what I might expect to happen next. Will call doctor in the morning, but am a little worried now.