Use the Page Setting functionalities to Hide or Un-Hide your pages from the Menu.
1. Click the Pages link on the top menu or the Plus + button on the page tabs bar to open the Pages & Navigation window.
2. Hover over the pages list and click the Page Setting icon.
3. The Page Settings window will open:
4. Check or Uncheck the box: Display Page in Menu
If the box is checked: the page will display in your menu
If the box is not checked: the page will be hidden from your menu
(Hidden pages are still published, to set a page not to publish, use the "Page Visibility" setting)
5. Click OK to preserve your work.