Featured Image Catastrophe

I was trying to put up my first post in a while. When I went to add a featured image, the option was gone. The editing panel just went straight from “Revisions” to “Categories.” Searched around but no sign.

Tried a few things recommended by Google but could not make it appear. After a while, I came across a suggested work around: add a featured image block, upload your image, delete the block.

I followed those steps, but since I deleted the block I cannot change the image. The image is also still showing at the top of my post, which is unwanted. Please help.

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