In some cases, some people may use "Preview" so instinctively, they may overlook the limitations. We see the confusion, occasionaly, in Blogger Help Forum: Get Help with an Issue.
Where is my page? There's no selection, under "Pages to show", even!The blog owner does not realise that unpublished pages or posts won't be visible, outside the page / post editor, and the "Preview" window.
In some cases, the confusion is not apparent, until we view the Pages or Posts menu - and see the "Draft" caption, next to the missing pages or posts.
If you really want to view the page or post, outside the Preview window - maybe to check the links - you have to Publish. In most cases, you can just Publish, then modify / update as you continue.
If it's so important to see the page or post - and you do not want it to be visible to your readers - setup a test blog. Then, copy or edit the page or post in the test blog - and Publish at will.
Just don't be unduly alarmed, when you look at your blog - and don't see the page or post, before you Publish.