My worlds are never in my updated minecraft 1.0 game when I go back to work on them

Ever since the new minecraft pocket edition update I've been having trouble getting my worlds to stay in my game. When i leave the game they delete themselves somehow. It crashes and when i get back in my world is gone. When i first got into the game after updating it it said global resources reset and that the global resources caused the game to crash. It did that a lot for a few days. Now its just not saving my worlds though.