When the battery runs out it doesn't mean you have to start from scratch. All you have to do is buy a new battery put it in and hit download and you'll have a everything you had. Same tama, items and friends! So calm down, all you need is a new battery and everything will be fine. The batteries don't cost much! ^_^
^ What you do is unscrew the back of the tamagotchi off. Then take out the battery that's already in there and put the new one in. Then hit B and press download and everything will be back to normal!