The menu on the left side of my screen on SOLIDWORKS 2020 SP3 disappear about 4 hours ago and I can't figure out how to get it back. I am not sure what the name of this sidebar is, but it is where the part tree (among many other things) lives. Without this side bar, solidworks is 100% useless because all options are displayed there. Why did it just disappear on me? How do I get it back?

To no avail, I have tried the following:
- restarting solidworks
- restarting computer
- restoring toolbars to default 
- even reinstalling solid works

SOLIDWORKS ​​​​​​​Menu bar ​​​​​​​Edu ​​​​​​​