I was on Ortho evra for a year and then a month ago I switched to Yasmin birth control. I have had unprotected sex with my boyfriend this whole time even when i switched. My only thing is that i just now started my period today and it is very light but with a lot of cramping, but im supposed to start my new pill pack tomorrow. Does this mean that I could possibly be pregnant or that just the effect of new birth control pills?