It could also be something you're eating/drinking. I've found that coke, even caffeine free coke, will give me a mega headache for the rest of the day. If the vitamins don't work, I'd definitely do a food journal for a few days and see if there's something that's triggering the head pain.
Thank you I will try anything
Estrogen can give quite a headache, and estrogen levels increase a lot during pregnancy -- try vitamin B 100 and magnesium (be sure to take the magnesium only a half pill at a time or it can give you stomach cramps and the runs).