Page publish error

I added a page to my theme successfully. When I click on the menu item for the new page however it takes me to a strange site with a different theme with a page error above

“Page Not Found
The page you are looking for might have been removed, had its name changed, or is temporarily unavailable. Please try the following:

If you typed the page address in the Address bar, make sure that it is spelled correctly.
Click the Back button in your browser to try another link.
Use a search engine like Google to look for information on the Internet.”