I have a squirrel that I rescued from the back yard of a friend's house. He is about 8-9 weeks old, and has been perfectly healthy ever since I took him in (he was about 3-4 weeks at that time). He has been fine all day long, but about an hour ago, as I was about to feed him before going to sleep, I picked him up and noticed that he was cold. I put him on my floor and he could not walk straight. He took a little bit of formula, but not much. He is still very lethargic, but I don't hear any "clicking" (though I'm not even sure what that means). Every time I sit him down or pick him up, he just kinda curls into a ball.
I need help now. ): I don't know what to do.