I agree topsie. My Christian name is alright, but no-one has called me by that for over sixty years. I'm known by my nickname, which is totally different. So when dentists (aaaaaghh!), opticians, doctors, phone-banking people etc use my 'first name' ( a bit of a cheek anyway, since we aren't bosom pals) I don't recognise it as 'me' at all. I had 'sedation' for a colonoscopy recently, and came round with a nice nurse shaking me and saying this strange woman's name over and over. Very bizarre.
To try and stay on thread, a very, very hard thing to do is to steel oneself to actually submit at the dentist's and sit in his sinister chair. My legs are heading for the door while my mind is trying to persuade me to sit down. Same for the colonoscopy. I had to lie voluntarily on a bed, surrounded by six (yes, six!) strong-looking nurses waiting to grab my limbs, while the sedation was administered. It was so hard to conquer my terror and stay put without punching an unfortunate nurse on the nose and making my escape! Those are hard things to do.