I'm guessing from your update that your hosting is not with Dynadot? When you change name servers they take time to update on all computers and ISPs. For now, you can get around this problem by checking on your domain by either visiting http://privacyhedgetrees.com (without the www.) or by checking your website from a public computer or one at work. But Dynadot has a tool planned to help people with this problem... see https://www.dynadot.com/account/forum/f6-engineering-corner/web-page-snapshot-175.html for more details. If your hosting IS with Dynadot, make sure the first two name servers are set to 'ns1.dynadot.com' and 'ns2.dynadot.com'. If it IS NOT hosted with dynadot (i'm assuming instead that it is hosted with secureserver.net) try setting the first two name server entries to 'ns1.secureserver.net' and 'ns2.secureserver.net'. Again, make sure you check on a different computer to see if your website works there before assuming there is a problem.
Sounds like a caching issue. Sometimes restarting your computer helps. If not, Raph's suggestion of trying your website from a different location is good. Often you just have to wait a couple of days for the cache to expire.