Hi I really feel for you b/c I am in the same boat.
Sorry if I missed it, are you male or female?
I heard vit C is associated with copper and this lends to estrogen dominance which could be causing the anxiety.
I have two types of anxiety:
1. Where my brain feels calm but there feels like there is a motor in my stomach that wants me to keep moving. If I am alone and lying down, I could feel totally relaxed and even calm but the slightest bit of stimulation including moving or talking to people or being in public causes me to have this agitated anxious state. During these times, cortisol lowering supplements do not work. They have a rebound effect and make the anxiety worse or even make me feel depressed.
2. Emotional anxiety. That kind of anxiety where I am overcome with worry and all I want to do is get up and pace. It could even be sub-conscience. I could be watching a tv commercial of 2 people on vacation and then i will have that "ugh" moment and then feel very anxious that I can't calm down. Upon reflection I will realize the commercial triggered me b/c deep down I know that I am in a bad financial state and cannot afford to go on vacation. When you are in this state, no amount of trying to talk yourself out of it will do b/c it sets off a chemical reaction in your brain that is hard to interrupt with a pep talk. For this I would try Joe's suggestion. It hasn't worked for me totally b/c I have other hormonal issues going on that I am trying to sort out which I hope will help with this type of anxiety.
I find when I go in the wrong direction in my treatment it sets me back a month or two. Like it takes my body that long to reverse the effects of using the wrong supplement.
Acupuncture also helped take me out of a very high stress state once. It can be costly if you go to a good practitioner but will worth it to help calm you down as this additional stress and anxiety is not helping you.
Another thing to focus on is your diet. I had been using supplements but haven't been very good about my diet b/c I work long hours and its hard to be strict with my food. One thing I noticed recently is that carbs make me feel worse. if I eat a high carb dinner I am bound to wake up with an adreneline rush in the middle of the night.
I think it has to do with insulin. When you eat lots of carbs it increases your blood Sugar which causes insulin to go up help lower your blood sugar. This will actually make your cortisol levels go up too, b/c cortisol is trying to prevent your blood Sugar from dropping too low. So if you are hypoglycemic you will have these adreneline and cortisol surges especially in the middle of the night. You will also have anxiety issues if your body doesn't produce enough cortisol so has hard time mustering up energy b/c of blood Sugar spikes so it relies on adreneline. Or too much cortisol b/c of too many carbs in your system and cortisol is trying to compensate.
I find if I had a very stressful day that I used up my energy reserves and I am bound to wake up several times in the middle of the night with an adreneline surge. I am going to try this concoction of 1 cup oatmeal, I cup applesauce and 1 tablespoon of almond butter before bed. It was recommended by a nutritionist who works with a lot of athletes to help stabilize their cortisol levels during the night.
Hope that makes sense.