The content in my menus are…messed up?

I’m having a bit of a freak issue here so I’ll try to be as clear as possible.

Everything was functioning fine a few days ago. Yesterday, I wanted to try to hide the “featured image” in the actual single posts, so that I could just use it as the thumbnail for the post without the picture being in the post.

I THINK (I don’t clearly remember…my mistake) I deleted something like `<?php if ( (function_exists(‘has_post_thumbnail’)) && (has_post_thumbnail()) ) { the_post_thumbnail(array( 200,200 ), array( ‘class’ => ‘post_thumbnail’ )); } ?>
<?php`
from single.php and it worked.

However, just now I went to my menus and clicked to see how things where, and it’s all messed up. I have 2 images of each thumbnail.

ALSO, when I click the picture or article title, I get an error instead of being shown the article.

Did I screw something up bad? Is there a way to go back to the original codes?

Please help ??

domain: https://www.strengthsociety.com