Oh no, poor Max. Shaking and tail tucking are definite signs that something is wrong, and that he is in discomfort/pain. Could be so many things, something simple like anal glands, or more serious. When my Max started behaving differently, it was because he had a corneal ulcer.
Is he pooping okay and on a normal schedule? Scooting on the floor? Is he sensitive to touch anywhere on his body? Walking okay? Anything unusual with his eyes -- squinting, blinking too much, tearing, or sensitivity to bright light?
I hope you find the answer quickly. If it continues, a vet visit is the only way to go. Can you look into Care Credit to spread out the payments if necessary?
__________________ Kristin, Max and Teddy |