Not an advice, just wanted to mention that if you are so worried offline, so to speak, some of it is bound to eventually leak through into the together time, and few people like it when the other person comes across as desperate or clingy. Also note that in most cases people get dumped in person, or sometimes over the phone, not by email/text/facebook status update, so the most dangerous time is probably the first few minutes after you meet up. Hope none of that happens to you.
If he was anxious and likely to experience a self-fulfilling-prophecy-failure before, he's probably twice as anxious now...
I started going out with a fantastic girl a couple of weeks ago. Everything is great, except that whenever I've sent her a text message or email requesting something and haven't received a response yet, I experience significant dysphoric anxiety, fearing that her response will be not just "no" but "no and I don't want to date you any more". This is due to brain chemistry or personal history, take your pick—either seems like a possible explanation to me. But there's certainly no evidence supporting the idea that this is likely to happen, nor is the anxiety helping me prevent it or helping me in any other way.
Does anyone have evidence-based advice, or pointers to same, on dealing with this kind of issue? It is the only splotch on what have otherwise been the best two weeks of my life.