I'm sure it's just a closing line, like "Best Wishes" or "Take Care". But I over-analyze too, and my inner child is always on the alert for anything remotely rejecting. So, inner child would be suspicious T means "Get well, already, so I'm done with you", when inner child can hardly bear to be without her for a week, even. I think that's what you're honing in on, subliminally, but I'm sure it's just a nice saying she does, to not be too short on the return email. This is so hard, to always worry about what T really means, but be patient with yourself and try to trust.