Every night around the same time, i get nauseas.?

For the past 2 weeks now, I've been getting really nauseas around the same time every night. I can be sleeping, and I get waken up from being nauseas. And i don't know why. I am sexually active, but I'm on birth control and take one every day when my alarm goes off. My boyfriend and I still use condoms, but he eventually pulls it of so he can "get off." But, every time he's close, he pulls out. Is it possible I can be pregnant? Please help.