Illness aside, you are experiencing what happens after being out of the game for a while. You want this woman, but the more you dwell on it, you wanting her morphs to wanting what she represents-- sex, companionship, a better life, etc... and this turns on the part of your brain that doesn't want to screw it up. These conflicting impulses (wanting the girl and not wanting to screw it up), will cause mental friction, e.g. a spike in anxiety. This is totally natural, especially considering you've spent four years out of the game. Add whatever has crushed your adrenals, and you have the recipe for what you're talking about.
You've proven to yourself that this isn't a freak occurence, that you can go out and meet other women. I would concentrate on that fact above all else, and when you go on your date, don't try to be something you're not-- be honest, tell her she's so hot she has you tongue tied, tell her that you've been out of the game for a while (you don't have to tell her why)-- women are fantastically intuitive, and if you try to cover up your anxiety by being Mr. Cool, she will sense it's a thin veneer unless there's a copious amount of alcohol involved.
If you're looking for something near-term, I suggest Vedic meditation, the kind where you inwardly chant a meaningless mantra for 20 minutes 2x a day, and allow your mind to devolve into increasingly abstract states. That is great for dispelling anxiety.
But honestly, the cure is meeting more women, getting their phone numbers, getting more dates, generally saying f*** it, and taking more risks in the sexua| arena. That is the way to break through the wall of fear.