Drink a glass or two of water before taking anything. If that doesn't work, try a little caffeine. Then try Tylenol. Even though its technically safe to take during pregnancy, its always better to try going without first.
Tylenol extra strength WORKS MIRACLES
I got headaches in my first trimester and tylenol didnt work at all... you have to drink at least a gallon of water a day, i also drank a cup of coffee and it actually worked... but not all the time just when the headache was in bearable... hope that works !
If you want something more natural try peppermint oil you can buy it in a roll on stick at the health food store. You put it on your temples and neck and it losens the tense muscules. You can also drink mint tea. Peppermint or spearmint they are natural headache supressers.
Keep well hydrated too. That has a lot to do with the headaches too. Yw