What Causes Nausea After Starting Seasonique?

I have been on Seasonique for about 6 months now and I have noticed that I feel extremely nauseous since I started taking it. I will get stomach aches and random nausea. I shouldn t be getting my period for another week but I already started getting really bad cramps and have been spotting for about 2 weeks now. I am mainly on birth control because I get bad cramps. What is a birth control that would help better with that and is the nausea a common side effect?