One thing I might add is that there is a difference between anxiety, panic, and stress. In terms of chemicals, panic seems to be based around adrenaline, whereas stress releases cortisol. Anxiety I believe is based around norepinephrine, among other chemicals.
The main thing to remember is that you can consciously cause all these different chemical reactions to happen, and if you do, you will store this in your cellular memory, which means that you will establish sub-conscious triggers which activate with increasing frequencies to create an ever-worsening problem.
The largest advise I can give is to consciously remain positive and focus on happiness, thus, creating sub-conscious triggers which lead to increasing positive neurochemistry, rather than negative.
You may also take heart in the fact that you can re-assign cell memory if you practice the manipulation of your sub-conscious mind via conscious neural-reprogramming! This means when you consciously realize you are anxious, panicking, or stressed, instead of feeding the negative chemical reactions, try your hardest to focus your conscious mind on visualizing a cellular memory of a positive experience or re-direct your attention to an external experience that is positive. It is very hard to do this at first, but the more one does it, the more one re-programs their triggers and can eventually eliminate these problems over time.
Still, one has to be always sub-consciously vigilant as new experiences may lead to re-creating old bad states which reset the problem! But you also cannot contumaciously go through life trying not to enter these states of consciousness, as whenever you try not to focus on something, you ironically will hyper-focus on it, as the conscious mind cannot "not" do something, it either focuses on something, or relegates that task to the unconscious mind. Like when you try to maintain eye contact you end up not focusing on what is actually being said, for example, in a social anxiety situation.
You can also use anti-anxiety drugs to treat the chemical part of the problem, but this ends up re-directing the cellular memory to memories of using the drug and feeling better, thus how these drug addictions begin in the first place, as someone actually learns to consciously defeat anxiety by taking drugs, the very act of taking them, instead of being direct about it.
Still though, as most people in western civilization do not develop any form of real conscious or internal reality, it will be a very hard thing to start, harder the longer one has suffered, but is always possible.
For that matter, drug withdrawal anxiety is the exact same, but it is actually the psychological association of taking drugs that is the anxiety state remover, the drug itself just changes the chemistry, not what causes the chemical reaction to occur.
