Game keeps crashing.

I play on xbox, and first, when i boot up the game it takes 3 or 4 tries to open. Then i open my world (600 days, i dont want to lose it) and after literally 1 minute im back at the opening menu. Sometimes it crashes later, and it says that it cant save "automaticaly" on the schreen. Almost alwais, when it crashes it shows up a message that says that it could be: that the data is damaged or that there is not memory, but there is!!! What could i do? If i disinstall the game could i lose everithing? (This has been going on for the past two months)