Don't worry about your diet just eat the same as usual. Any better will benefit you the same as us all, but it will not harm your urine to any great extent. Forget about the movie it is just a TV production and you cannot be sure of the facts because it is heavily edited. I have used old urine on my skin (did not do much), washed my hair with it, bathed my eyes in it and fasted on all my urine for two weeks at a time and drank it through my nostrils which is excellent for sinus problems. If you have something wrong it will usually fix it and I believe it will keep your organs youthful.
Just drink what you can, when you can. Morning urine is the most effective.
I am sure your colitis will go away, but it might return again some time. If it does look at your diet and try to determine what is triggering it. For the meantime keep drinking. I would like to know when you find relief.