virus

It's likely some form of malware, but not a virus.

You should download and run Malwarebytes, it’s a very popular scan tool among veteran users here in the Community, and it’s the only one recommended by Apple tech support folks. See if it can identify any malware you may inadvertently have installed. The free version is probably all you need at this point.

Run this analyzer and post the results here:

Etrecheck - http://www.etrecheck.com/

See http://www.etrecheck.com/faq for information about the basic version which is free and how to upgrade this to a power user version.

Using Etrecheck - https://discussions.apple.com/docs/DOC-6174

Extra tips about settings to have it check all parts of your computer, and how to post long reports to the Apple Support Communities window: https://discussions.apple.com/thread/250599211?answerId=251149996022#251149996022