IMO you don't need the psyllium if your stool is thick. Taking it shouldn't increase your frequency. It can increase or loosen stools for people with colons. It does the opposite with us, it sops up water and makes our stools thicker. Your frequency at 4-5 stool a day sounds great to me.
We have 30% more bile in our BM's than when we had our colons than when we had our colons, that's why my ostomy nurse told me to get it off of my skin right away as it's more like battery acid!
I would expect your blood to be going away if you are still using canasa. It sounds to me like you have cuffitis as you are feeling like an acid at your back door. That is what my active cuffitis sort of feels like. It in the rectal cuff and has ulcers on it, or at a minimum is inflamed and red. As our stool collects there it aggravates it and we can feel it more - I call it internal butt burn. That sounds a lot like "acid" to me. I too go every time I can as I think it is better to not let it set in my pouch and allow it time to give me more internal butt burn (acid stools).
Pouchitis, cuffitis and c.diff all cause a lot of stools and you had non of those from the beginning. That's one of the reasons they are so hard to tell them apart with out a pouch scope. For whatever reason they are treating you for everything.
Since you have been on this treatment plan for a while now doesn't it seems as things have calmed down? Will they do a pouch scope on you now? If I were you I'd like to find out what is wrong, without the risk of bleeding like you were.
I hope the doctors can do something to help your fears.
Please let us know and take care!