My DS was having issues with anxiety and panic attacks and believe it or not, it was caused by the foods he was eating. After eliminating dairy from his diet, the anxiety slowly, but surely went away.
We have since removed gluten from his diet and continue to see improvement.
You would be surprised how many common foods can affect your body. I was.
I also know of several people who have seen a decrease in fibro symptoms by sticking to a gluten-free and/or dairy-free diet.
I hope you find an answer soon. Anxiety can be very difficult to live with.