HTTP Status 404

I am not tech. savvy. My website structure is different now and only the home page can be accessed. When I try to login to edit the webpage I am given an error message: HTTP Status 404 – Site does not exist. And the url is different as well: http://shieldstonepethospital.vetstreet.com/wp-login.php?redirect_to=http%3A%2F%2Fshieldstonepethospital.com%2Fhome%2Fwp-admin%2F&reauth=1appen%20

Before it did not have the wording “vetstreet” in it.

The webpage url is: http://shieldstonepethospital.com/home/

Please help me I am lost