Anybody else conditioned their brain to automatically think certain things whenever the anxiety appears?

I had a pretty bad experience with extreme anxiety a year ago and I started obsessing over the meaning of life and other horrible existential thoughts. Now I’m doing very good and only sometimes get anxiety (usually on my period, like now) and I immediately start thinking about the meaning of life. Which makes me even more anxious. I’m so annoyed. I did it without realising it and now I can’t undo it