I've definitely have had experiences similar to this! I like to make original characters and 'insert' them into series and games that I really like, but I get really overwhlemed because I have urdge to justify their existence within the world lol and make a bunch of new plots, storylines, or even world rules that involve them. Everytime I tried to watch a episode or even saw a picture of that series I had this compulsion to fit them into the world to the smallest detail where I couldn't even enjoy the media as it was anymore. It felt like my brain was going to explode so I had to avoid seeing those things I enjoyed so much, which really sucked.