Confused

Victoria

So, I'm really trying to figure out what's going on. My husband and I are trying to have another baby, well when I'm completely off my birth control, I don't get periods AT ALL. I'll go months without one. As soon as I start my birth control again because we've given up, within two weeks I have one. Because of my migraines, they have me on a progestin only birth control. So what could be making this happen?