hormonal imbalance

Back in December, I started taking the pill (I got it from one of the doctors at the clinic I go to). However, in March, I went back to get a check up and a refill, but had to see another doctor, who then told me to stop taking the pills because she didn't like her patients taking them. In May, I asked the doctor who originally gave them to me to start me on them again and since then, I've had a hormonal imbalance. I bleed about 3 weeks out of the whole month because of it and I've gone back to the clinic and even the hospital a few times, but they just keep saying it's normal. Has this happened to anyone else? How did you deal with it? Are there any medications I could ask to take to prevent from losing so much blood?