How to talk with coworkers when your mind is silent?

I find conversation extremely difficult and exhausting. Someone talking to me is especially distracting while I'm at work, so I tend to stick to my scripts when dealing with patients: "how can I help you?" "Can you verify that address?" "I wanted to let you know we have flu vaccines in for the season...." (ugh lol)

But then my coworkers try to talk to me sometimes.... I usually respond pretty reactively, like, "That's really cool!" or "Oh, that sucks. I'm sorry that's happening." Sometimes I do feel feelings, so I'll literally say something like, "Hearing that makes me feel happy" or "I'm proud of myself for [action]" (one of my older coworkers giggled at me for saying that).

I just don't usually have any thoughts in my mind to say. And my memory is awful too as a bonus. How are you supposed to verbally talk with someone when you're like that? I'm also AuDHD and have OCD and idiopathic hypersomnia too, so I'm just really not built for social situations.... Any comments are appreciated :3

Also, I resonated with the Just Doing and the Unsymbolized Thinking in the Descriptive Experience Sampling Codebook.