LegoMasio1400

hey! i was just wondering if anyone knew why when i try to go onto a world i made in single, it says "shutting down internal server", then says, " out of memory!" "Minecraft has run out of memory. This could be caused by a bug in the game or by the Java Virtual Machine not being allocated enough memory. If you are playing in a web browser, try downloading the game, and playing it offline. To prevent level corruption, the current game has quit. we've tried to free up enough memory to let you go back to the main menu and back to playing, but this may not have worked. Please restart the game if you see this message again." then gives me the choices of back to the title screen, or quit game. both of them shut the launcher down. talking me to the launcher screen. can anyone help me??? Thanks, LegoMasio1400