I don't think you totally missed the opportunity, and like the edits that Newmama made to the e-mail. I'd suggest sending, today:
"Thanks for your concern about me last nite, but I'm realizing that I'll be just fine. I do feel that something needs to be said for communication's sake. This is my take on it..." etc.
I think it's important to get these things out there. You need some firmer boundaries in place, if nothing else than for your own emotional health.
