I have never heard of that~! Usually the cause of anxeity which I have is worrying. When you may not even know your worrying about anything! Although low iron and anxiety both can cause you to pass out or black out~!Anxeity has to do with your nerves~! It is also very hard to overcome!I have had it for about 5 years and it comes and goes .Talkto your doctor they may be able to help!Anxeity can also cause tightness I the chest and a rapid heartbeat.Hope that helps ya!
Good luck,
viking chic

It's true that stress can cause anxiety, but it's not always that simple. There are a lot of chemical or hormonal imbalances that can contribute. Also emotional history(post traumatic stress,phobias,etc.) talk to a doc about all your symptoms. If physical problems are ruled out, there are some good meds that can help. Stress is one thing, but if is as severe as panic, meds and therapy can help. Also, pay attention to whatyou are doing when you feel this way. Might help you see what "triggers" the anxiety. Hope this helps. Good luck!