Hi,
First of all welcome back!
I had never heard of a "low residue" diet before and took the liberty of doing a bit of research. It's definately going to be a challenge but i'm sure one that you are strong enough to meet!
The doctors must have let you speak with a nutritionist. Did you discuss your concerns with them? What did they say? I'm sure you are not the only person that has ever had to deal with the same thing. Do a search for specific support groups. I only had a bit of time and wasn't to successful myself, but there has to be something.
Any course of action will be one day at a time. Breath, relax...I understand stress is a big factor. Hopefully, someone on here will have some specific suggestions, just keep reaching out and don't panic.
I wish you all the best and am glad you're here.