I am also 3 years post subdural haematoma surgery. I still get headaches though they are not as bad as they were in the first few months when I had very little support and very little sleep! At last someone suggested Amitriptyline which has helped with the headaches and meant I can sleep better. I took 1 tablet at night until recently when I have cut it down to half a tablet because of the side effect of constipation. I haven't been to the Doctor before cutting down. It is very difficult getting an appointment usually only a phone call is allowed. I agree hydration is important. I Also find to long on the computer and any sort stress brings on headaches.