Hi Fito,
I'm really sorry to come back and read that you had further complications. It happens, and no matter how hard you can try to reassure someone that most of the time, things get better, there is always some who face further challenges unfortunately in their healing process.
Rich has given you some great advice there and just try to rest and manage it all the best you can.....I'm wondering if a GP will prescribe you Valium to get you through your worst days - It's not something lightly prescribed but it can provide immense pain relief - it might be worth going back to discuss how bad you are feeling too and how to best help you deal with the stress it all brings. One day you will be so much better I promise and you won't feel as awful as you do right now.
No matter how physically horrible it all feels, just seek some help mentally if it's too overwhelming and if you are feeling stronger, you will be able to cope so much better.
I can't even begin to advise you of my coping strategies with pain because I was fortunate enough to have a very simple fistula compared to yours. I would say continue the Sitz baths for as long as you feel you need them & use a hot water bottle or heating pad too at this time because heat helps for sure in encouraging the all important blood flow in the healing process. I do feel that sadly, your case is one of the more extreme, but even these cases heal slowly over time, and at some point, you will be looking back on it all as a distant memory. You will get through this & I do wish you all the very best whilst trying to deal with it all.