Options?

Cat
So I have very heavy and horribly painful periods so I have been on the pill almost since I've started menstrating. But about a year ago, my body developed an immunity to it and I've been switching around different types ever since. My doctor recently took me off it to regulate my system and told me to think about what form of control I should try next, so I have come to all of you to ask if anyone knows what would work best? Or has a similar issue? I don't want any control that would stop me from getting pregnant for longer than 7 years because I do want to have kids eventually. Thanks everyone!