i have always had a normal period except for the month of april and may. April 22 2008 i had my period for just two days. may 18 2008 i started on time but period has been very light for the past 3 days and i started to cramp bad. I had never cramped like this before. I passed a blod clot the size of a golf ball, and i am still bleeding very light. I went to the emergency room and my doctor said unrinary track infection but i have had alot of those in the past and i really don't think that is what is because i urinate normal and i don't have a burning or any kind of vaginal pain just cramping. i am really concerned of what this really is.