What can I do to bring my hierarchy back? I have no idea what I did, but my hierarchy is gone. I'm trying to make a VR character, but I can't finish it without the hierarchy. It shows up if I open another project, but I don't want to start over. Can anyone help me? Thanks in advance!
You must have accidentally closed that panel.  You can actually make any panel in your view an outliner by clicking on the button on the top-left corner of the panel.
To open it again as it was, simply click and drag from the top-right corner of the properties panel and drag down, then change the new panel you just created to an outliner.