Things can sure be complicated and confusing! I find it so at least. I think the gas and urgency are completely normal for your stage of recovery and will improve.
With the leak, I did feel unwell but assumed it was normal post surgery. I did go back into the hospital for iv antibiotics. I really don't know if things would have been helped by earlier treatment.
Re fistula (pouch to vagina) it started with air in the vagina within the 1st month maybe. It's hard to remember. It changed to a thin mucous followed by thin yellow liquid. It is mainly that liquid now but can sometimes be bits of frank stool, lettuce shreds, etc. Crazy. It leaves the vaginal tissue very raw.
Am I correct in assuming the yellow mucous is in your vagina?
Re treatment, it's been a process over 4 years but have not had success: 2 flap advancement surgeries, an attempt with Remecade and then Humira. This summer I went to the Cleveland Clinic for a consult for a new type of treatment but was not appropriate for me. I'm mostly able to live with it. I try to keep the stool on the thicker side. Today's probably not a good day to comment though as it's not been a good one fistula wise.
I wish you the very best through this. I'll be thinking of you.