I don't know where all my objects went. I think I pressed something wrong, but when I press slash or alt+H nothing happens. All of the meshes are grayed out. I think I am in the right layer. Here is a picture.
It looks like maybe you hid the whole Collection (though its hard to tell because I can't see all your objects in the outliner). Pressing Alt + H will not bring back a hidden collection. Scroll up to the top of the outliner and see if the Collection is hidden: