Even though you aren't a medical professional, all these points seem to be quite valid in the contributing factors to anxiety. I too have personally felt the benefits of exercise and avoiding coffee while being anxious for whatever reason. And you're spot on with the mineral deficiency point too. This is especially true of Vitamin D. The sun can do wonders for your mood. I've fixed myself on certain days by just getting into direct sun and spending 30-40 mins in it listening to a podcast, speaking to a friend or just taking a walk in the park.