This happens to me all the time (I feel like my limbs are changing sizes to football pitch lengths). It's called proprioception or kinesthesia.
Mine may be related to old head injuries. I'm also of a similar age. I have a neurologist, but unless something shows up on a CT-scan or MRI they don't tend to do much in the way of treatment.
It's an unusual presentation of proprioception that I've only regularly seen on this website! Most presentations seem to think the outside world has changed size, so seeing other accounts on this page has been reassuring. PTSD, head injuries, migraines, the pandemic, etc.... makes figuring this out tough.
Useful has been trying to put together a complete medical history. Unless you've had the same doctor for your whole life, your medical history will be wildly incomplete. None of those analogue records will be in your file.
Good luck!