I get headaches all the time. When I'm not pregnant/breastfeeding, the most helpful thing is codeine. Since I didn't want to take that during pregnancy/breastfeeding, things that did help me were a) drink more water - dehydration is one common cause of headaches (and pregnant ladies need more water), b) get more sleep, or c) take a panadol (didn't help THAT much but maybe better than nothing at all)...