Why would a period last for weeks on end?

This is a little bit of an uncomfortable question for me to ask but I`m going to ask anyways. In November of 2010 I had my daughter. While in the hospital the nurse gave me a Depo-Provera shot. All seemed well and I stopped bleeding in around a month. Then all of the sudden I started to bleed heavily again 3 weeks later. It lasted 3 additional weeks. Well my body is still not back to normal. I have 5 children and after each child everything returned to normal within months. But, not this time! I have always had a regular 28 day cycle. Now I`m bleeding for more than 2 weeks. This last time I got my period it started out very slow, like spotting then it came full force with huge blood clots. So big and so heavy that I soaked threw my pants & had to throw them out. When it stopped I was happy to say the least. Four days later I started to bleed again and it hasn`t stopped. It`s not a heavy flow but enough that I do have to wear a pad. It`s been almost 3 weeks and I`m very frustrated! Let me also add that I had the essure procedure in January and I had my confirmation test on Monday June 20th. I wonder if that has something to do with it. It`s so hot out and I`m so uncomfortable wearing a pad all the time. I just want this to end! I`ve been reading blogs about the side effects from the depro shot and I`m sad to say I think I may be one of the women that`s have the bad side effects but it`s been 8 months now. Has this happened to anyone else? I`ve given it 8 months and in my mind I`m thinking this is normal but obviously it`s not so I do plan to set up an appointment with my doctor but that`s going to take a week or so. Any advice or has anyone else gone through this. I`m at my wits end as to what`s wrong with me.