birth control

in september, I had stomach surgery and was then diagnosed with endometriosis. I explored my options for treatment and went ahead and got an IUD to play it off safe. well since getting my iud in November, my period has not stopped. it hasn't put a stop to my sex life, but it has costed me a lot of money for tampons/pads as well as a lot of pain with cramps. I went back to my doctor, and she went ahead and prescribed me a birth control pill. well I expressed to her my concerns about it, she still pushed me to take the medication. it's been about a month now and I still haven't started taking the pill. I've heard way too many horror stories about it, and I'm just way too scared to take it. I'm just unsure what to do, whether I take the pill or just wait out the period to stop on its own. any suggestions?