metformin and birth control

I've been TTC for 8 months now and found out I have pcos. My gyno told me to get back on my birth control to help regulate my periods, because I didn't have it for one month, and to drink metformin twice a day. I've been drinking my birth control once a day but kinda loosely and drinking my metformin the way I'm suppose to. I want to get pregnant and fear the birth control is really making take steps back. has anyone gotten pregnant while taking birth control loosely? I kinda want to stop taking it but I don't know what to do... any advice?