[FryFry]

She started acting strange last friday. My uncle came over, and she was barking like crazy at him. She always does this, so to snap her out of it I always tap or poke her on the side of the neck. This time when I did it she yelped. The next day she didn't greet me at the door when I came home from work, and she would shiver/tremble on and off. On sunday she seemed to be getting back to her normal self. Then all this week she was perfectly fine. She got excited when I came home, she strutted and acted all perky when I took her outside, she would play with her toys. Come Wednesday afternoon she started acting strange again. She was on the couch and jumped down like something scared her. She ran upstairs, and wouldn't come down unless someone went up and got her. She sometimes shivers on and off, and hangs her head down low. She seems very sad, and sometimes she'll slightly hunch her back when she walks. She still eats and drinks, although I don't think she ate much today. She just runs upstairs and curls up in a ball under the bed. I did remove a tick from her head 2 weeks ago, and I'm not sure if she could have lymes disease or what? I was checking her ears today for ticks,and when I touched her left ear she whimpered. I'm really scared, so I made a vet appointment for Friday. She means everything to me, and I don't want anything to happen to her. Any ideas on what could possibly be wrong?

INFO: 4yr old, female yorkie, not spayed.