When I start a safari, I find myself on other pages

In safari preferences extensions, turn off all extension . Then turn them on one at a time till it duplicates the problem. Then delete that extension. If no extensions in safari download and run Malwarebytes.https://www.malwarebytes.com/mac

There are no known Windows-like Viruses in the wild that self replicate and affect macOS, because of the underling UNIX  Foundation and Permission Limitation. 

The Only thing this Antivirus software is protecting is the Bank Account of the Developers and for zero return to the User aside from the problems this software creates.

The The Built in Security  is all that is required to protect the computer.

Should “ Certain & Specific Software “ referenced from above be installed - it will negatively impact macOS. It is suggested, to download directly from a respected ASC Contributor, the application Malwarebytes for Mac. 

It is free or paid for added features. 

Run the Application and it should remove the malware / adware. Once done, restart computer and test.