canada,
Welcome to the forum.
I'm so glad you found us, but sorry you have to be a part of this terrible club.
It's good you're going to get some probiotics, and ask about rectal meds too - they can both be very effective.
Tedd is right, plenty of us,including myself, testing negative for gluten and yet found gluten to be problematic.
L-glutamine you say didn't make a difference after 2 weeks?
How did you use it?
L-glutamine powder ( 1 heaping teaspoon in a little water or juice on an empty stomach) can be used to help diarrhea symptoms. BUt l-glutamine powder used long term will help with colonic repair.
You may want to try slippery elm powder too.
If you are interested, there are things IMO that you can control, which will have a direct impact on your disease, the symptoms you experience and their severity.
I was able to control my UC into remission through various supplements, probiotics, diet modification as in going gluten and dairy free and being on the Paleo diet, and LDN , low dose naltrexone.
For more info on the protocol which has put me into remission, please go to this link: https://www.healingwell.com/community/default.aspx?f=38&m=1666318 , and look at the 11th post.
I hope you feel better and let us know how we can help you.