he next step would be to ask "why is that bad?" and "exactly how bad is it?"
Yes. Face the loss. What is the cost? We worry that if X, then Y, and fret all day over the uncertainty of X, instead of facing the loss of Y as a done deal, and knowing that we'll survive and life won't be so horrible.
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.