There is no way she should have been discharged in that state. Karen is right - some animals do take longer than others to recover from the effects of the anaesthetic, but regardless the vets/nurses should have kept her in and monitored her until she seemed truly recovered. I'm also a little concerned the vets reached straight for the antibiotics when they saw some blood in her urine, assuming she's a young kitty a UTI is not necessarily in the top list of differentials, plus they are not entering the urinary tract to spay her so effectively no risk of contamination there...

Do you know whether they used gas to get her under? The recovery tends to be more fractious in animals that are gassed down (rather than induced intravenously before being put on the gas), and behave as you have described, although I have never seen symptoms persist that long before. It would certainly be worth finding out everything that was used on her, just in case she has experienced an adverse reaction that could be avoided in the future. I hope she managed to make a full recovery - please update us when you can?