“Head discomfort?”

I have been experiencing a persistent pressure inside my head for more than a year now. The pressure is mostly mild and sometimes from the side of the head just above the ear towards the forehead but mostly I feel the pressure all over the head. I just don't feel comfortable inside my head. I forget very easily and I find it difficult to recall things that I have already memorized. I often get confused most especially when under pressure. Whenever I come across two things that are almost similar, e.g adopt and adapt, I get confused about which one is which. I have to put extra effort into articulating the words before I could them well. I used to be very normal until I started experiencing the above issues. Thanks