3 week period??

I've been on my period since the 3rd, it started kinda regular not too heavy just moderate and than it got a little lighter and than super heavy. Right now its my 20th day and its super heavy. I don't really have time to go to the gyno as the closest one is over 2 hours away and I don't even have a car. Any ideas what this could be? I took pregnancy tests before my period and I wasn't pregnant at any point