That's one of the dangers of e-mails. You can't hear the tone of voice or see the body language. I also believe she was being firm as well, but that's just IMHO. I think you may have to cut her some slack here. Doesn't she still have chemo brain? Not that you aren't allowed to feel your feelings...but just make sure you're reacting to the facts, not your perception through an e-mail which may be misconstrued-if that makes any sense.

Take care!