I own a miuchiz. They are little creatures which you raise up and you can use them to play online on a special place called planet mion. It's so much fun. The website for miuchiz is www.miuchiz.com.
Did you keep the game on pause. If so, it won't leave until you keep it out of pause. It stays a few hours then it leaves, and then it leaves then you can take care of the baby. I hope that helps, check out your tamagotchi. PM me if it helps.