I've been getting some awful headaches since 13weeks. MW told be at 16 weeks that it eases off at 20 weeks (along with the constipation), and the last week has def been better. I've taken paracetamol once most days, sometimes more and MW said this was fine.
Its worth getting your BP checked a few times though. Later on in pg they worry about preeclampsia with headaches, but your BP does go up with this. The nurse at your surgery ought to be able to do this if you can't see the GP. My lovely practice nurse has done mine a few times just to put my mind at ease.