Just my two cents to add to everyone's thoughts -- I've had odd perceptions of empty spaces, or separation between parts of my body, so I know what you mean. I had GK only a week ago, so we certainly might have different reasons for the feelings.
One little 'exercise' I learned as a meditation teacher decades ago, --In order to make sure students were "earthed" (ie focused) before they drove off in a car was to have them focus their attention in their feet for a minute. We're all so focused in our heads that it's easy to start "floating", which might be similar to your feeling taller....?
But I certainly wouldn't discount a balance/medical cause either. As a long-time patient advocate for family members, and now myself, maybe consider finding another doc? One about who you don't automatically think, "He/she is going to dismiss what I say....etc." Or, forcefully reeducate your current doc......
Story: I live in a small town, albeit with some good doctors around. Even the one my husband and I see took a full year or more to finally listen to my husband about his symptoms, which ended up being Multiple Sclerosis. Now, a few months later, she's already recognized the symptoms of MS in another patient.
And I was lucky - right before my MRI/ AN diagnosis she'd had another patient nearby with an AN, so I benefitted from Sharon being first. (BTW, Sharon -- somewhat of a non-internet person -- and I now have our own local AN Support Club! We'll probably be meeting at one of the Casinos.....(!) So, Raydean, there's two of us in western Grays Harbor County now, three of course including you!)
Anyway, I have been complaining of balance problems for the three years I've been seeing my doc. It hasn't been that serious, so I never pushed it. But then hearing loss, the MRI, the AN diagnosis and I start reading. "Research shows that 90%+ of patients present with hearing loss, not balance problems, blah, blah...." That's what I read. So I relay this to my doc, and mock-shouting add, "THAT"S BECAUSE YOU DON"T LISTEN TO US!" And she wholeheartedly laughed and agreed.....
That's the kind of doctor I need; one who will listen if only eventually! I also make sure she is aware -- and I'd like to make the younger folks on this board aware -- of how recently "It's all in your head." was a prevalent mantra of doctors. It profoundly affected the welfare of my mother (and me) in the 50s and 60s and 70s. Medical education has changed dramatically since then (at least that's my amateur patient observation), but it's one of those things I don't want people to forget because Doctors Listening is an important component of modern health.
Sorry I get carried away; it's just that these things are important to me.