Korvo,
You have my deepest sympathy, mate. I suffered from a major stress problem (still do, really), but now that I know it is only stress (rather than an impending heart attack!)I can control it more or less.
One of the main problems with busting stress/anxiety is breaking the pattern that leads to it. Another is recognising the syptoms and dealing with them before they become a major problem. As you already know, the anxiety-hyperventilation-more anxiety loop is a horrendous thing. My trick is to spot it starting, then stop the hyperventilation. Forcing yourself to take small, short breaths usually works. Many people drive themselves into hyperventilation because of helpful suggestions like 'take a few deep breaths and you'll get over it'.
The patterning thing can be a real problem. Example: coming back from my girlfriend's house (many years ago) I had all the symptoms of an impending attack whilst approaching a set of traffic lights. Concerned, I turned back. Two minutes later I felt better, and turned back for home, only to feel the same panic building as I approached the lights for the second time! Solved the problem by calling myself all kinds of rude name and busting through the situation.
It's all about playing head games with yourself.
Good luck.