Alright bro here it is:
The simplest exercise is just proper deep breathing. Inhale deeply, hold for one-1000, two-1000, then exhale slowly and completely for one-1000, two-1000, three-1000. The exhale should be done in a way that you feel like there isn't a single molecule left in your lungs to push out. At the end of the exhale you will be pushing with your stomach and diaphram to get that last bit of air out. Sounds simple but the point is that it will teach you to breathe correctly - from your stomach instead of your chest.
Another exercise that will help more if your are having an anxiety attack or are about to lose your temper is to do the same as above but on the exhale you will say four words as you exhale and as you say each word you will touch your thumb to each of your fingertips on each hand starting with the pinky. So big deep inhale from your stomach, hold one-1000, two-1000, then exhale and during the exhale slowly say a chant like "I".... "like"...."getting"...."laid" as part of the exhale. You canchoose any four words you like. On each word you will also on both hands touch your thumb to the tips of the other four fingers on the same hand. When you exhale the final word you should be just barely able ot push it out, really getting your lungs empty. The point with this exercise is two things: you are doing correct deep breathing in conjunction with focusing your attention on the words and the touch of your hands. The deep breathing helps slow your heart down and the focusing on something, expecially something tactile or with a pattern helps fix the anxiety, panic, anger, etc. I can't remember what this technique is called but I have witnessed people who had PTSD from bad shit fix their panic by simply tapping on their wrist with their fingers.
I'm frequently in very stressful situations, notice my heart rate increasing, then I'll remind myself to breathe correctly and I can get it back down. Takes some practice but it is worth it.
Another chemical fix for anxiety is beta beta blockers and those might be safer than the Klon. Ask your doctor about it. I know that with a beta blocker you can be in a shit your pants I might die right here situation and stay smooth and cool.