If you write an article that prompts you to check for plagiarism, you know you've plagiarised

Couldn't agree more. Once the thought to check for plagiarism crosses your mind, you have more than likely already plagiarized and are now looking for a way to mask it and hide it from coming to light.

I don't think it's really difficult to create original content. There's so much going around us that can turn into content if you just know how to write. These are things going on around YOU. Experiences unique to only you and no one else. Writing from your own experience and point of view can not be that difficult.

Well, most people pressure themselves into writing even when they don't have content, and that ends with them plagiarizing because they just read up some generic stuff on the internet and try to spin it in their own words and pass it on as theirs. There's no pressure to blog. If you have nothing to write, be a reader for the time being then. Read and engage with others until you have something to write about. It can't be that difficult to do.

I'm sorry this happened with someone close to you. You're an awesome teacher and hiver, and I and several others are witnesses to it. Stay strong and don't be shaken by this.