Categories/Archives not working?

On my website, I am using a layout that I converted into a theme myself. For some reason, when I visit my categories/blog archives and click on a category or month, I am just returned to that page (or one that looks exactly the same for that matter) instead of seeing a list or my posts from that category.

I’m not sure whether or not I did something wrong.. if anyone has any ideas or anything, I’d be glad to hear them. 😀