Some cats are picky about their bowls and don't like to use ones that are too deep, wide or whatever. Maybe try a different type of bowl. Also some cats prefer running water so try turning on the bathroom faucet to a trickle or getting one of those pet water fountains to drink from.

BTW cow milk generally isn't a good thing to give a cat except in very small amounts as a treat only. Many cats are lactose intolerant and it can give them diarrhea.

You could always try adding just a bit of water to the canned food to make sure she gets a bit extra.

Overall if you vet has looked her over and said as long as she's acting ok otherwise to not worry, then I wouldn't worry just keep an eye on her for any changes.

Good luck.