What a screw-up WordPress is!!!
It might not actually be WordPress that screwed up. What theme were you using before you did the upgrade?
LOL…did some Ghost just suddenly come in and make the changes?
Give me some useful comment or nothing at all.
I went through past years comments and YES, WordPress upgrades CAN
change the website – though WordPress SAYS they cannot. LIE.
Can someone tell me how to undo the changes the WordPress upgrade
made to my website?
Sure. I’ll give you some useful comments.
Allow me to elaborate on the importance of the question you avoided answering:
If you were using the default wordpress theme, and spent “months” customizing it: wordpress over-writes the theme on a full upgrade. Your changes are gone. All of them. However, the solution is simply to restore your customized theme from one of the regular back-ups you made.
If you modified the default theme, rather than working from a child theme, and an upgrade over-wrote your changes, the fault is yours.
If you regularly modified ANTYHING on your site for “months” and did not take regular and complete file and database backups of your site; the fault is yours.
In any event, the supreme solution to all of your issues is simply restoring your customized files from your last back-up. If you don’t have them, that’s also your fault.
Now, would you like to have a productive dialog that might actually end up assisting you? Or does that solve the issue?