I don't really think stress/anxiety is the cause I think like many other things its a symptom of the cause. You should try out some supplements to help you out with the anxiety problems, I know how frustrating those can be. Personally I found I mainly had anxiety because I had cornflakes hanging off my lips but it did also feel like something was off with my nervous system. At one point I took 3-4 different supplements @ once to help deal with stress anxiety, it helped but didn't cure me.
ATM I'm still under stress but no more anxiety problems, not sure why the anxiety stopped but just glad it did.
Take a look at this article, maybe it can help:
(tips at the bottom of article)