Well if you still have your tab from the very beginning you can put the tab back in. That's what i do sometimes.
Then if you're lucky if you pull out the tab very quickly the screen still stays blank, if it does don't squeeze your tamagotchi or the battery will connect again. If this doesn't work then just leave you tab in.
When you want to play again, just pull out the tab and press resume. That should work, it does with me!