Birth control

So I'm on birth control and I have been for about 3 years now. When I get my period they barley line up with my water pills and my cramps are still horrible! I've been to the doctor twice about this and they've changed my pills twice but still the same thing. I don't know if they're working correctly or not but I pray they do. I have this black patch on my face from the pills that the doctor calls melasma. It makes my body seem like it's pregnant when it's really lot. Anyway do you guys think it's working?