I was having bad headaches, I'm now 20 weeks. Went to docs when they got so bad they were sending me to bed for 2 days!
Mine turned out to be a sinus infection. I think headaches are common in earlyish pregnancy. It could be BP related though its very very unlikely at this stage of pregnancy - worth checking it out just in case.
The thing that seemed to help me was 4head, its a kind of menthol gelstick , about 4 quid from Boots. Worked like magic and safe in pregnancy.