Before I was married I started using BC to help my horrible cycles. We weren't active so it wasn't a 'contraceptive' it was just to help ease the pain. About 2 months before we got married, I decided to stop using it. I didn't want to have a hand in possibly killing a future child of ours. According to the Church, I could still take it for medical reasons, but my reasoning is; I can suffer for a week for the sake of my children.
So, all that being said, as long as you and your bf are not active, which I read you are working on, then your bc would be medicinal not contraceptive. After you get married, however, you may need to look into other alternative medication for it.
Talk to your priest. This is a common issue and one you shouldn't be ashamed of!:D Good luck, you are in my prayers!