When I would get a headache, aspirin did not help. What has helped me is massage therapy. With the pressure you are putting on your back with being pregnant, this will loosen up the muscles and just a wonderful stress release.
I live in the Brighton area and have used two EXCEPTIONAL massage therapists. They are trained to perform massages on pregnant ladies.
The other thing that you could do is whole food supplements. Fish oils (make sure they are without mercury), B vitamins (helps with stress), calcium/magnesium/vitamin D (other than the obvious benefits, magnesium helps with nerves and muscles).
If I can be of further help, call me at ###-###-#### or email me at ____@____.com last thing on the massages...I had several massages when I was pregnant with my daughter. They really helped me to relax. Then when I had my daughter, on her due date, it was only 5 1/4 hours of labor and without any drugs.
M.