It is controlling your thought-process that you really want. In this case, there are breathing meditation techniques that you can easily learn from the internet. Once you are familiar with this meditation technique you will need to advance to mindfulness meditation with which you are taught to watch the rising and falling of your emotions and thoughts. However, this mindfulness meditation may be a problem as it is not readily available in the internet, but if there is a Theravaden Buddhist temple in your area, you may be able to learn both methods at the same place. The meditation master there may teach for free. Meditation is the best and quickest way to control your anxiety and panic attacks.
One last word: taiji may be said to be a form of moving meditation besides the martial aspect, but the meditative part is seldom taught. Of the "three treasures" that a taiji-exponent aspires to harness, ie Jing (essence), Qi (energy), and shen (spiritual), the last treasure, shen, the spiritual attainment, comes after decades of practice (with instructions). You may not want to wait that long and there is no promise that you can achieve the three treasures in that order, yes, it has to be in that sequence; you can't jump the gun.