Break through

I've been on birth control for about a year and a half, the first pill I had gave my break through bleeding every month and severe migraines. I switched to a new brand and I've been on it for about 8 months now and didn't have any problem with it until recently. I hate break through bleeding about 3ish weeks ago and I just had break through bleeding again today!! I don't know if it's because my hormones are off if my body can't hold 3 months worth (I skip my periods) what should I do?