Sudo command is not working

Hello, I use an iMac and I use the command line. I was converted to a standard user because I reinstalled macOS Catalina 10.14.6 (long story why I did that) , and now whenever I use the sudo command (which I need a lot!) it gives me this error: "Nicholas is not in the sudoers file. This incident will be reported." and I cannot use the sudo command anymore. I have done SO MANY Google searches on how to fix this you wouldn't believe it, and I run into permissions errors for everything I try that I found on the Internet. Boy are there lots of solutions out there, and I spend hours on end finding them and just run into permissions errors. Here are two of them: "Sorry, try again." and "<main> attribute status: eDSPermissionError

<dscl_cmd> DS Error: -14120 (eDSPermissionError)". There are lots more permissions errors I run into to. Cam somebody please help me get the sudo command working, I need it! (and I need a solution that DOES NOT require use of sudo-for the time being I can't use sudo to get sudo back!!!) Please help.