Take a look at
http://moodgym.anu.edu.au/welcome its an online free CBT therapy thing and gives you a good idea how CBT helps to to change negative thoughts to positive ones. I had some CBT and it really helped me at the time, although i think i needed more sessions than i could have, that was one to one sessions, there are also group sessions but i havent heard such positive stories about these. Loads of poeple say CBT is defo the way forward with anxiety, i would defo encourage you to try it.
Good Luck xxx