Widgets not showing

I’ve been working on a trial website and I tried different sidebar layouts with the widgets I intended to use until I found the best solution for my site. Unfortunately, seemingly all of a sudden, some widgets stopped working.
The WooCommerce Cart widget still works fine, but the Search widget isn’t shown correctly (it used to work in the header bar, same place where I have it at the moment), as is the dropdown menu to sort products. If I add a custom title to the Search widget, the title gets shown but the text area and search button won’t show up.

Here’s a rundown of the main settings I’ve tried to fiddle with to try and make them work again:
“Home page” and all the product pages are “default template” and “default layout” under the Page editing options
Under Settings->Reading: Homepage displaying a static page, Home page set to “Home”, and article page left blank
Under Customize->Design->Default layout (for each of the three options): first layout on the left (layout with sidebar on the right)
Customize->Design->Site layout and Page Listing Display Type are set on “Boxed layout” and “Large featured image” respectively
Sliders are off, responsive menus are off, options under the Additional tab are off.

What could have gone wrong? I’ve already deleted and reinstalled the theme to no avail.

The page I need help with: [log in to see the link]