Re: My cat won't eat while we're away.
For being so curious, cats are creatures of habbit as i'm sure you're probably already aware. I find it strange that the cat didn't eat at all (not even a few pieces). You not being there could have affected her enough to cause her to freak out (specially if she demands attention like some of mine do.). Was she originally a stray cat? Traumatic incidents will also permanently scar a cat mentally.
One of my cats managed to open a window and was 'pushed' (as far as i can guess) by one of the more aggressive cats out of the window (because he wanted to look out of the window). To this day (almost 2 years later) she wont go near a door or a window.
Does she wait for you to come home from work, sitting there starring at the front door?
I might suggest, next time you leave for the weekend to leave a video camera running to see what she does. If this is the case, I would suggest weening her off of her addiction/problem slowly. Start with going out on friday nights, then maybe leave friday night and come home saturday morning, then go for 2 days, and then to 3. Once she gets used to the idea of being home alone I doubt you'll have any problems like this. Is your wife, or someone typically home with her all day long?
As far as your current emergency situation (her shaking), hopefully it'll correct itself since she started eating/drinking again. Are you 100% that she didn't drink any water at all? Typically cats (in the wild) are creatures that will stuff every possible ounce of food in their stomach then lounge about. As long as she drank some water during the time you were gone she should be fine. But if you're 100% she didn't drink any water at all, an IV may be required to replenish her fluids. Watch how much she drinks in one sitting as well, as learned in Auschwitz, a starved person will eat and drink themselves to death as their body cant handle it. But 2 days is a long cry from the malnourishment received by people kept at various nazi camps.
If it were my cat, as long as she didnt display any additional symptoms to those you've already seen, I'd hold off 12-24 hours to see how she does. If the condition worsens or you see additional symptoms, i'd take her to the vet immediately. Just make sure to keep a close eye on her.
(I'm not a vet, so take my advice for what its worth)