New Page created is not listed in Navigation bar

I created a new page for my web site (alkpurusha.net) but the page Header — called Newsletters — does not appear in the Navigation bar at the top of any page.
I have delineated its number sequence on Page options of the Newsletter page.
The only thing I can think of is whether there’s enough space on the Navigation Bar, but surely it should simply carry on to a new line?
Advice?