I have the same problem as you. I realize it could be due to my illness and medication. I drink coffee to focus and stay awake.. I also exercise to keep healthy. Nobody in my family has dementia though. So, no worries there. However, brain fog and tiredness are issues that I'm constantly battling. Some times I feel as if my head does not belong to me. I feel detached. I try to sleep it off when this happens. I don't have insomnia. I sleep too much and remain tired. I don't know what to make of it.