I think it is VERY early in your recovery. I can remember I was so happy my grandkids came to visit the week I came home (they are 3,5,5, and 6) but I found I really relished quiet. I t really was such an effort to converse and interact and walk about to the den and the kitchen table -especially with the eye and the full head that is still pretty numb. And then our faces are crooked (mine is 80 per cent back now) Of course everyone encourages you to walk and eat and nap, but listen to your body and when tired or maxed out mentally go to bed. (The week after I came home Hurricane Sandy struck and we were without power! But we survived!!)
I am three months out (I am also 65 but in good shape) and just getting around to driving ...when in a store, I start to feel tired-I think it is the fullheadedness, or "weight" or "wonkiness" or pressure but I hope that gets better. I have been told I will get better and better. Like you, the doctors thought one thing going in, and then when they get in there, they can really see what is going on. But they said I would get better and I am. It is definitely better than one or two months ago.
Please give yourself time and nurture yourself.