Prozac, unfortunately, can cause anxiety. It's one of the more activating anti-depressants -- and it has about the longest half life of any SSRI. I think the full wash out period is about five weeks, but you should be feeling better well before that. The five weeks is how long it takes all the metabolites to get out of your system. The anxiety should be faded within a week or so.

I'm sorry I can't tell you that you'll wake up Friday feeling fine, but you should feel progressively better over the next few days. Also, once the Prozac is out of your system, if it was really entirely the Prozac causing this, you shouldn't find the need to continue the Xanax. That's good news, at least, right? Good luck.