If anyone’s interested, I tackled the other end of this problem (building a tolerance) in a blog post a few months ago:
https://medium.com/@TestingInProd/building-a-caffeine-tolera...
https://medium.com/@TestingInProd/building-a-caffeine-tolera...
I realized the degree of my caffiene sensitivity when I had to give it up. Just quitting my one cup of coffee a day was rough. (The headaches!)
Now that I should be able to consume caffiene again, I can scarcely look at black tea without my heart racing. I really miss good coffee and it's effects, so I'm thinking about doing just this myself.
It's hard to start however, now that I know that I'm basically cultivating an addiction.