I know what you mean. I'm always scared of a response to one of my texts. Sometimes I have to turn my phone off. I start panicking, as well, if someone doesn't reply. I'll start beating myself up about it, saying they don't like me, don't want to talk to me etc, even though they might be busy or might not have their phone switch on.
I think it's slightly easier for me on a computer, though. Mainly because I can't see the person's reaction on their face of something I've said. And they don't know who I am personally, so they can't beat me up (I was beaten up by an ex-best friend's boyfriend). It's much harder in person to talk to anyone, because I'm so scared of their reaction. I sometimes think that if I go up to someone then they will just walk away and ignore me, and I'd be so humiliated. It's bad enough paying for something at a till when there's no self-service