I've been miserable with a UTI for 3 days now. My doctor says until I have taken the Macrobid 100 mg. for 4 days that there is nothing she will do or change with the prescription. I am wondering if this is normal for a UTI to take 4 days on medication until it relieves me. Anybody have trouble with these infections? Is this normal to take several days to get relief? Please help with any advice. I'm trying to decide whether to go to the ER tonight or give it one more day.