[Fey]

m'kay, so I don't think she's having a reaction to the spaying, that would have been right after the surgery. It could be hairballs, but usually they'd be making horrible hacking noises to get rid of it, you'd notice.

Just a heads up, the food you're feeding, doesn't matter what they say the flavour is, it's alllllll chicken based. They just flavour it differently. Most cats don't seem to like beef flavour so I'm not surprised she's turned her nose up at it.

I'd say definately give her yogurt and a bit of pumpkin(the giant cans of puree are like two dollars, and the rest can be used to make delicious pumpkin bread for you!). If she's trying to pass hair, or has just an upset system both will help re-set it to normal.

The drinking of water is good, just make sure she isn't drinking and excessive amount(like a full bowl) then having pottying issues. This can be a sign of a bladder or kidney infection.