I suffered from severe headaches during pregnancy with my DS. For me the solution really was as simple as drinking more water. Much more water. I have always been a water drinker and easily drink 64 oz. a day, but during pregnancy my needs are higher.
I know that sounds ridiculous and you have probably already looked at your water intake. But, just double check. During my last two pregnancies, I have found that the headache will begin creeping up on me until I "catch up" on my water.
One of my friends had the same issue. She did go to the hospital and they put her on ringer's lactate IVs. After two bags she felt much better. She had no idea that she was dehydrated. It is so easy to be when you are pregnant.
Another thing to double check is that you are not eating foods with MSG ( including hydrolyzed vegetable proteins, autolyzed yeast, hydrolyzed yeast, yeast extract, soy extracts, and protein isolate, etc...). Even if it did not bother you in the past, it may now now that you are more sensitive in pregnancy.
I am so sorry that you are in such pain. It can effect everything, can't it? I do hope that you find relief soon.