What Just Happened!

So i just got done after a while of map editing and putting stuff in the correct places and i saved the scene. I saved the project. I then open the scene up again booom all the stuff is in the heirachy but the scene and game screens show nothing! What just Happened?!

probably nothing just try double clicking something in the heirachy to focus on it

This has happened to me to. I lost my game 4 times to that. What you want to do is exit, immediatly. Then open your scene again. Don't save, don't do anything else.