As Sannah says, you can hide with someone next to you but, also, your T needs to see your face/expressions.

Everyone has their personal distance they like and that's neither right/wrong, just a genetic/built-in/human thing. It sounds like yours might be "closer" than his is.

His training is important and, it's only your "problems" that are discussed in the room so is better if you have a problem :-) than if he does (since that would take away from his attention/abilities to concentrate on you and your problems).

Too much space should not be a particular problem between two people but, as you've noticed it is for you, that should be discussed. It is my experience with therapy that my discomfort is a good indication of what needs to be worked on (I use to "red flag" thoughts and experiences in my head to look at later, when I wasn't in session where it was too difficult at that time to look at; eventually I was able to look at those feelings in therapy, with my therapist).

It is unfortunate that your T just started the practice "suddenly" and didn't "warn" you first or discuss it, after having done therapy in the old office "your" way before.