Sunken sidebar on random posts

Hi all!

A couple of hours ago, I suddenly noticed that my left and right sidebars have sunk to the bottom of some of my posts. Not all the posts, but several, all from different dates, and there seems to be no correlation that I can see.

For example, on today’s post the sidebars are at the bottom:
http://emilyluxton.co.uk/february-insta-photos

But on the post before that one, everything is fine:
http://emilyluxton.co.uk/travel-tips/protecting-valuables

I’ve read through both of these posts:
https://en.support.wordpress.com/html-troubleshooting/#fixing-a-sunken-sidebar
https://wpbtips.wordpress.com/2012/05/19/sidebar-at-the-bottom-and-related-issues/

And I’ve tried everything outlined. The setting ‘WordPress should correct invalidly nested XHTML automatically’ is switched on, and I’ve updated the most recent post.

I recently switched on ‘Image Share’ from the Sumo Me widget, which is the only major change I can think of other than publishing a post and scheduling one for this Friday. Since the problem occurred after this, I tried deleting the app, clearing my cache, and revisiting the site but the problem was still there – so I have reinstalled the app.

I already posted this in the troubleshoot forum, but I have been asked to post it here instead. You can seethe original thread here: https://wordpress.org/support/topic/sunken-sidebar-on-random-posts?replies=2#post-6644027

Can someone please tell me if my comments.php is correct or if I need to change anything? I’m reluctant to touch anything as last time I tried to change the comments.php I got the ‘blank screen of death’ and had to restore from a backup. http://pastebin.com/yVT13Dar

I’m very, very bad at technical stuff so please explain things as you would to a child!

Thanks so much

Emily
http://www.emilyluxton.co.uk