It's happened to my friend's v1. She was only on 1st Generation. Her battery was low, so she reset and downloaded it (couldn't be stuffed to get a new battery) and she loaded back a Chohimetchi (that's the character you got). She was on 21st generation. The hearts were emptying rapidly. Chohimetchi ran sideways to the hurdle. Chohimetchi was at 99 grams and its weight was an upside down 44. And yes, it was definitely a v1... the games are Dance and Jump.
Great, now I feel something like that's gonna happen to my 85th Generation v1. Just try doing what binary said.
MsKitty89, it's care, but you can get characters by debugging (if you have a Tamagotchi Connection, hasn't been proven to work on Tamagotchi Connexion but I HAVE seen a debug circle on the Tamagotchi Connexion circuit board).