You might think about taking more vitamin C, I take a total of 10 grams a day, myself, but not in one dose. You might try taking 1 gram twice a day instead of once and see if that makes a difference. You might also try niacin, it works great for my nephew for social anxiety. You could try taking 500mg of niacinamide. My nephew takes the hexanicotinate form which is more expensive, but niacinamide makes him lose his appetite. Hexanicotinate is another flush free form of niacin.

You could also check to see if you are being affected by any food allergies, they can cause tiredness. To do that you have to avoid potential allergens for 4 days. The easiest way is to only eat foods you do not usually eat for 4 days, especially do not eat gluten or dairy products or eggs. If you feel better after 4 days then you can gradually try the foods you have been avoiding to figure out which ones are causing the problem. One important thing to know is that food allergies often increase the heart rate, so you may be able to solve that problem if you discover that you do have food allergies. For more information you can read the book "brain allergies" which mostly deals with how food allergies can cause mental illness, but they do talk about one woman who was fatiqued from her allergies and the instructions they give for finding out which foods are causing problems apply to any type of symptoms.