Most icons missing from menu bar and other toolbars

I'm suddenly having issues with so many of the toolbars, it couldn't fit in the topic line, honestly. Most of the icons have disappeared from my menu bar, basically all of the OS-related icons. The only ones that are displayed are ones I've downloaded (one other one I downloaded isn't displaying, but all Mac-related ones aren't showing, such as the battery indicator, volume, WiFi). Apple icon isn't showing.

Also, I don't use Safari so initially I didn't think it was an issue, but I checked just to see, and indeed the icons on there (back, forward, share, etc.) aren't loading.

Aaaaaand on top of that, the toolbar for Finder is messed up. Just like Safari, the icons are just blank, all of them. Here is a screenshot that shows what I'm seeing. This didn't happen when I booted my computer up, it suddenly happened while I was in the middle of using it. I thought maybe I was low on RAM (my PC back in the 90s would do that) so I rebooted and it still was doing it. Shut it down and it's still doing it.

Not sure if it matters but I haven't downloaded any software or updated anything lately, in fact I've been constantly ignoring the iTunes update for the past couple months. The last update I did was the OS update they put out.