Please help

So I have been taking birth control for about two months now. I take it perfectly. Everymorning 6:30-8:00. I've never even missed a pill. Just recently I've been getting real nauseous and adventually end up puking but the nausea and vomiting usually begin about twelve hours after taking the pill. And explanations ? 
I am sexually active. Very carefull I make him pull out even with a condom on.