Permalink problem

I’m trying to set up a permalink that has the name of the page as the link. i.e. http://www.mywebsite.com/commercial/

But when I go to customize the link… it won’t let it be anything else other than http://www.mywebsite.com/commercial-2/

Why is it putting the “-2” at the end of the link and how can I get it to stop? Even when I go into the page and use the Edit button near the permalink it still tacks on the “-2”.