Sounds like it might be OCD related. The funny thing about OCD is that the intrusive thoughts and compulsions can vary so widely between people and be so random, so it can be easy to focus on the content of the intrusions rather than on the experience of having such intrusions in and of itself.

I formed an entire made up language in middle school because I kept getting made-up symbols in my head, and it combined with the delusion that something was trying to communicate with me in a language that I had to construct/decipher. It's over 10 years later and I still sketch some of the symbols in random places sometimes when I'm stressed out.