No Longer Able to Log into Admin

Hello,

Im trying to access my websites WordPress Admin and Dashboard but I am unable to get to it – my website is https://www.rosssimmonds.com/WP – First problem is that my theme is gone completely – Second problem is that when I click Admin I am directed to a 404 Error page.

The URL used to be https://rosssimmonds.com/WP/wp-admin/ however now it doesn’t take me anywhere – I believe that the URL itself is changed now or something cause all my images that are hosted at the same address cannot be reached when going through the URL Address.