I'm sorry you are going through all this - wow, you have been through a LOT. It can seem like it's a never-ending nightmare, but you will come out of it. There's some excellent advice above, especially those encouraging you to live one day at a time right now.
Briefly, like you, I was initially diagnosed with UC, but after experiencing fistulas, abscesses, and other cr*p, the dx was changed to Crohn's. I had a seton in my first pouch-vaginal fistula for nearly 7 yrs. My 2nd peri-anal abscess/fistula was septic; after a seton placement in that one, a pouch diversion with end ileostomy, and a yr of recovery, I finally had the pouch removed. (I have to add that the setons were not horrible for me.) Due mainly to fear of the surgery, I waited too long, and the pouch was finally removed when it was about 25 yrs old. The surgery went fine, although there were a few post-surgical issues (not pouch related). My biggest concern was being sewn closed - aka Barbie or Ken Butt - but my very experienced surgeon stitched me closed on the inside, and I really had no problems with healing there, or with anything other than minor pain there for a couple weeks. Also, my stoma was revised when I had my pouch removed, so it's longer now and easier to care for. If you do end up going with an end ileostomy, these are just a few things to keep in mind and ask your surgeon about.
In the meanwhile, I can only suggest to try to stay positive (I know, so much easier said than done). Keep hydrated best you can - I drink diluted "Liquid IV" all day long to help in this respect. Go for walks if you feel up to it, try to gain some strength back from your ordeal. If you can, join a support group for ostomy folks - there are some decent ones on facebook that have given me some great tips with dealing with my appliance (e.g., The Real Ostomy Support Group), and with dealing with life with an ostomy in general.
I wish you the best for you and will keep you in my thoughts.