Custom Content suddenly stopped working/disappeared

I’m one of the few still using the Panel theme (but I love it and it works for me!) but suddenly over the past 24hrs, my comic site is broken – Panel uses Jetpack which allows me to post comics and use the archive page functionality and also scroll back and forth through the comics (or go to a random comic).

Jetpack is installed and activated and I see ‘posts’ in my dashboard but ‘comics’ (custom content) has disappeared as an option. I’ve installed backups from weeks ago when the site was fine and still I’m getting the same issue so it seems like something has maybe changed with Jetpack?

I’m looking at possibly changing themes to “Toocheke” which is a similar type of theme as Panel but I hope I haven’t lost the copy that went along with my 100+ comics with each of the custom posts…

Does anyone have any suggestions? Thanks in advance.

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