I am glad to hear that you have already gone to see your eye doctor
, as that is always the first thing I recommend when people have these kinds of symptoms. Your eye doctor can rule out trouble with nearsightedness as well as more serious eye diseases, and it sounds like they have done this already.
Therefore, since the symptoms are still persistent, I think you should probably talk to your primary care doctor
now. They will be able to perform a complete examination, including a neurological examination, to make sure your blurry vision is not due to a serious neurological problem.
Assuming they rule this out, I think the most likely possibility, especially given that you have 'pressure' and not just blurry vision, is going to end up being simple eye strain or fatigue. Depending on what kinds of activities bring on the symptoms, your doctor will be able to give you some recommendations on how to minimize this. For example, these symptoms are very common in those who work at a computer all day, and the symptoms can be improved by taking regular breaks from the computer screen and rearranging the work environment to minimize glare on the computer screen.
Good luck, and see your primary care doctor as soon as possible!