Content link takes me to the right page but does not display the products

I'm new to Squarespace and I'm taking over a half-built site that my predecessor started. Currently I'm working on adding pages to the navigation bar, but I've run into a problem with linking the pages.

I'm using the Om template to create some online shopping pages. Pages I have linked to that are not in the navigation bar work just fine; the link takes me to the page and shows my products. With the pages in my navigation bar, clicking them will either take me to the right page with no products, or I'll get a "broken link" error message.

I hope I'm explaining this well enough! Thank you.