What could be causing these symptoms?

I know no one can tell me what’s wrong with me—I have a doctor’s appointment but not till November and I am at my wits end here. I’m just looking for information. I started menstruating at the age of 13 and it was always normal, every 27 days or so, never had a problem with cramps or anything. For the past 2 years, my periods have become increasingly difficult. They are heavy, sometimes I pass clots, and I am in pain. Sometimes they last 12–14 days. My last period lasted about a week, then I stopped bleeding for 2 days and now it’s back in full force. Not only that but sometimes intercourse is extremely painful. Certain positions help, but not always. It is not a lubrication issue, it is deep inside. I have only been with 1 person – my fiance. I’ve been searching online for these symptoms and all I come up with are STD’s which I know I do not have. I was even tested just in case. Any ideas? I call the doctors office almost everyday to try to get an earlier appointment… no luck.