cannot connect to localhost (0) (no replies)

I am using MySQL community version and workbench for grad school- business analytics. Everything was humming along fine until I upgraded my macOS to 10.14, Mojave from High Sierra 10.13. Now I keep getting the cannot connect to localhost (0) despite uninstalling MySQL and reinstalling it twice. Meanwhile, the class days are ticking away, and I have to use my iMac (it is still on high Sierra) to do my homework. In System Preferences, the server is running. I can reinitialize just fine.
Help? Both of my business analytics professors are unable to figure it out because they live in PC world.