So sorry about your anxiety. Have I mentioned Dr. Claire Weekes' book/audiobook "Hope and Help for Your Nerves"? There are also clips on YouTube.

Have you recieved an offical diagnosis for ADD? If so, by whom? and how long ago was that?

Since you brought up diet... maybe you have food sensitivities... have you thought of eliminating gluten? An "elimination diet" (you can look it up) to check for sensitivites might be worth trying.