Is it normal not to be able to think of a single thing to say?
A big part of my social anxiety is simply not being able to think of anything to say. Even when I'm really trying to talk to people I just literally cannot think of anything to say to them. I'll spend 10 or 15 minutes walking alongside them on the way to work, going out of my mind with stress trying to rack my brain for anything to say to them, and I wouldn't think of anything the whole way. And if people ever comment on something, like about something at work or just anything at all, I can't respond because I just cannot think of anything to say about that. So I just reply with an "Oh" or a "Mmm", which must make them think I couldn't give a shit. Taking part in conversations is impossible for me. Even if I do ever think of a reply to something someone has said, I'll think of it about 10 minutes later, after the conversation has switched topic about 5 times.