Which birth control method is the best in case of endometriosis?

Hi doctor,

My periods will last usually for five days on average. It hurts tremendously even with pain medication and birth control. I would get horrible periods since I was about 12 years. In my 15 years age, I used to vomit on the first day of my period, but vomiting stopped in the past two years. Before one year I have been diagnosed with endometriosis and prescribed birth control to help ease symptoms. My current medication is only over-the-counter painkiller and doctor did not prescribe any medication as she felt it would not help me. I am considering switching from hormonal pill birth control to an IUD.

I have researched on the internet and I would prefer a hormonal method because I have endometriosis. My heavier periods and cramps sound absolutely horrible. However, I have also read that a lot of women experience weight gain and moodiness with the hormonal methods, the two things I do not need in my life. Which method is better for me? I am 19 years old, moderately sexually active with a serious relationship, generally healthy (prone to colds and flus), no serious medical issues in the family aside from my endometriosis and no history of cancer or ectopic pregnancies. Please suggest me.