Flu Shot

So I am having a dilemma.. Everything I read says pregnant woman should get the flu shot not only for them but the baby is protected for 6 months after birth. However I have read comments that some believe the mercury that's in the shot can cause autism in the baby. Now my GP says get it my OB/GYN is against any kind of vaccination during pregnancy. I am so confused. I am asthmatic so the flu shot is a big plus for me. I have been getting the shot for 17 years.. really don't know what to do.