Well...our chats were going OK (obviously; she opened up about some personal, painful stuff, at least to a degree). I can't speak for how or what she felt, but...it went from a mail virtually every day or so, full of wamrth and detail, to...not-as-warm mails...virtually overnight. Then it was a while before I heard anything again. I assumed it was down to workload, life, etc, but apparently not - it was covered by a pretty weak excuse - and so it went.
It was stupid and 'my fault', because I should have reacted in a more natural, human way. I never did quite learn that trick, though.
Does she know...I don't think so, and I guess I'll never know for sure. If I bump into her at some future point and there's no risk of collateral damage (i.e. we're both single, for some reason), then I'd probably, finally, tell her and see what she said. But with things as they stand, I'd probably take the position of 'Let sleeping dogs lie'.
Wise man. Going backward is rarely a good idea, I've found. Can't think of a time that a missed opportunity turned out to have been a bad thing, upon reflection.