I am wondering about femara fertility pills? Does any one know anything about this!!?

I got a trigger shot because I had two good follicles. I started bleeding around the time I should get AF. I want to make sure that I am not pregnant beffore I take my next round. What happens to that other follicle if you just get pregnant with one? Is there anyway that one follicle got fertilized and the other one made me start my period?