That was pretty rude.
I understand your anxiety. I started my career in psych. We never floated, but I chose to leave after a few years because I was afraid of losing my skills. And it is true, you do lose certain skills (and gain others) when you go into psych. I hadn't been near in IV in nearly 5y. I was really stressed when I first started to have to deal with "medical stuff." It came back quickly, but it took time.
To expect someone to just float from psych to a medical unit like rehab where you have the whole gamut of dx. and expect that nurse to take a full assignment and act as a staff member--sorry. Not without a lot of orientation, not without a skills review. Until I was satisfied that I had the skills to meet the basics for those pts., no way.
I don't care who did what back when; I've been a nurse for a long time too and worked in several specialties. I would never dismiss someone for feeling anxious about floating to an area he/she was unfamiliar with. That is ridiculous. Not when we're talking about making the person take an assignment and act as a staff member. Yet another prime example of why people leave nursing. Do you ask your opthomologist to do your colonsocopy?
I hope you can find a solution to your situation, maryx. Mine was to leave psych and get skills. Ultimately, I'm glad I did because it gave me more mobility, but only you can know what's best for you.