If none of the above has helped, check out Amy Yasko's site: "DrAmyYasko.com" and search for glutamine, excitotoxins, etc. You'll find info about glutamine as a contributor to excessive excitotoxin activity- which could explain your irritability on taking it. Sorry I can't do a better job explaining this!
There are other ways to address leaky gut- testing your food allergies , some herbs (slippery elm?) etc.