My Sims 4 game doesn't want to work. (Please Help)

The game is fine. I go on, I can make a new game, or I can chose a pre-existing game. I can make households, but as  soon as I go in to gamplay it resets be back to select a world. So, I've just made my sim, I buy him/her a house, I try to go in and play, but it won't let me??? I've been playing this game since it came out and this just recently started happening.