Check this site out
http://****.com.au/2007/08/vitamin-b-and-c-for-anxiety.html
Yes, vitamin c may help. Adrenal glands help you cope with stress but cannot do that when their not properly functioning. Vitamin c may help them function better.
If your going to try this take 1000mg twice a day with your meal.
Vitamin B may help more as it can directly help with anxiety.