Can't see walls/sims/furniture in live mode sims 4

So just a little while ago I sent my sim into the kitchen to "Grab a Quick Meal" and then suddenly I couldn't see any furniture, sims, or wall inside the house. If I zoom out, i can see the outer walls and roof as well as sims walking by. I tried using the page up button but once I clicked the up arrow, it wouldn't let me go back down (greyed out). I've exited and re-opened the game, to no avail. I've done some googling and can't find an answer. I don't know much about all that software technical stuff. I'm on a Macbook Pro. I read something about moving things and saving then deleting something about trays and stuff but I don't know what that is really. 

Any help would be greatly appreciated.

Thanks!