Our Cairn terrier is 13 yrs old. Today I took her for her walk and she slipped alittle on her hind leg and after she was stepping down, she slipped again. She was able to finish her short walk without any problems. Then when she was lying down, I noticed both her eyes moving from side to side and eye brows twitching. She would not eat, until alittle later. Then she went out to pee and she was alittle unstable on her feet. She did pee and walk around some and seemed stable. Could this be a stroke or maybe inner ear problem? Thank you!