my minecraft pe keeps crashing

Ever since I updated to the new minecraft update I’ve been having a problem. I can play on my worlds but only for a limited time. After a few minutes the screen goes black, then the generating world screen pops up. After a few seconds i’m back at the home screen of minecraft. When i click back on my world my game freezes and i have to reopen the app to play. Please try to find this issue soon because some other people have been having the same issue.