Build Mode in Sims 4

When I start a new Sim in the Sims 4, I have no problem creating them but once I get to editing/building a house, that's when I run into problems.

In build mode, I like to start houses from scratch. When I use the wall tool, I build the wall but right after I let go of the mouse, it disappears. 

When I buy a house that is furnished but I want to upgrade the fridge or a couch, I use the sledgehammer tool and get rid of the old ones, but it will only delete 1 item at a time. When I find the object I want to replace the current one with, it won't let me place it. Or if it does, it disappears right after.

I just installed the whole game onto my laptop on the 26th so I'm not sure why this isn't working already. 

Any advice is greatly appreciated. Thanks!