Re: "Therefore, chances are that if I could be an animal, I would be. This makes a strong anthropic argument that it is impossible for me to be an animal."

Your priors say that you are a human. It is evidence that is hard to ignore, no matter how unlikely may seem. Concrete evidence that you are part of a minority trumps the idea that being part of a minority is statistically unlikely.

Since this is true regardless of whether or not it "feels like something" to be a bat, the mere evidence of your existence as a human doesn't allow you to draw conclusions about Nagel's bat speculations.