Hi Melissa,
Which browser do you use?
Unless you have changed the settings for saving the history of your browser, the last few days of history should be easy to obtain, e.g. Safari and Shiira have both a menu item called History, and under that you can see the last (Safari's default is 9 days if I remember right) days of sites visited (unless you have private browsing on). Maybe there you can find the URL you forgot.