I've lived with migraines for over a decade and through 3 pregnancies...
check with your doctor, but Tylenol should be safe. I was given T3 (tylenol with coedine) for a couple of mine while pregnant and nursing as well. I would try some other methods too though; ice pack at the base of the neck (you can alternate heat too...sometimes I respond better to one vs. the other), lavendar ess.oil at your temples, blue emu or icy hot like cream on your shoulders and neck, I also have a neck pillow - well the new kitten has it now
it's a fox stuffed animal - that has various aromatherapy herbs in it that I heat up and seems to help, and my personal favorite that works 9/10 times...massage.
Congrats on your pregnancy, hope it all goes well and you feel better soon!