I think you did the right thing, though I'm sorry you were disappointed. Even if it's not Covid, I could understand a T not wanting to risk getting a virus, as it could lead her to have to miss work, plus feel awful, etc. With Zoom being an option now, I can see her choosing that, as you could still have a session, though not in the preferred setting.

I imagine once (if?) my T resumes in person, if I let him know in advance that I had anything more than a mild cold, I could see him wanting to opt for Zoom. Even if he might have been fine with it before. I think many people are just more jumpy about illnesses right now.