I crash when I exit the nether

So I have a nether portal on my realm and I can go through it to the nether fine. But when I try to return, my screen stays on the loading screen that says Generating World. I can hear the sounds of the overworld and my player is there, but I only see the loading screen. I have to close down minecraft and reopen it for me to be able to play. I can't even exit to the main screen when it is stuck.