My 5 month old kitten fell out of a tree today. She seemed fine at first, but then started acting a bit strange. Although she didn't do it consistently, she dragged her back legs, tilted her head to one side, walked in circles, and began falling asleep sitting up, all while purring. I already took her to the vet, and they say she's fine. She has no broken bones, her pupils are fine, her blood sugar is normal, and she doesn't have a fever. She is doing much better, and I expect she will be back to normal soon. For now she's still sleeping quite a bit, had some trouble jumping onto the couch, and although she hates the car, never made a sound on the way to or from the vet. I'm curious to know what might have been going on. Any ideas?