I'm going to have to read this thread properly later (by which time it'll probably be about 17 pages!)
You weren't being irrational or wussy, allhail, because the risk is real - how statistically real depends on your environment at the time, of course - and, should he turn out to be an aggressor, you'd likely be at a physical disadvantage. But the fact you necessarily felt more nervous than a man would is a feminist issue!
Having said that - I used to write guide books in which there was a mandatory safety section. After many arguments with my male editor over this section, we eventually realised that I was writing from a female perspective. For example: I took it for granted that one would think twice before staggering, alone and drunk, down a dark alley in a large city. This sort of thing needed explaining in far greater detail (how, why, where, when, what to do) as men do not normally feel this sense of background caution.
With that in mind, it seemed men suffered from an inflated sense of safety, which was in fact unsafe. That's just as irrational as feeling extremely nervous.
I do walk around wherever I like - not from stupidity, but out of principle - and, in consequence, was attacked a fair few times on my travels. Men in that country, however, were far more likely to be seriously injured in attacks. I suspect this has something to do with their sense of affrontery: they got angry with attackers, where women are more prone to negotiate - and are mentally better prepared for the eventuality.
I'm not saying it's in any way okay that other people, mostly men, attack strangers, or that I feel there are definite 'correct' rules. But caution is wise, and absence of caution can be more dangerous than over-caution.