Your sense of humor will be essential for a positive recovery experience! There will be many challenges you will face when recovering from your Nissen (as we all do), and if you can laugh, and take things as they come, you'll be a much happier person. The more you struggle against what is, the more difficult you will find your recovery. It appears that many who have this surgery expect smooth sailing, and have a really hard time accepting changes that come with this revision of the upper GI tract.
There is no telling how your stomach will accept the assault that has been forced upon it. Having the top of the stomach wrapped around the esophagus and stitched there is no small matter. Your stomach is bound to rebel for a while, and the more you can accept that fact, the easier your recovery. Follow your recovery, don't try to force it.
My stomach is very sensitive, so even a year and a half post surgery, when it gets irritated (or my wrap gets irritated by roughage, etc.) I can get a bout of diarrhea. Hey. That's life! I have a "potpourri of poo"...it changes daily...soft, normal, diarrhea...it may change day to day, or week to week. If I get a lot of grumbling and gurgling in my stomach, I know I'm in for a bout of diarrhea. You'll be glad to know that constipation is very, very, rare. Yay!
All this is part of the game. I'm not sure everyone experiences what I do...everyone is different. I can only speak to my experience and what I've seen posted on this forum.
This too will pass. Try to hang in there and go with the flow! You're in the early stages of recovery, and there will be challenges until things settle down. I know the fact that you are at a desk job makes things more difficult. Things will get better as the weeks progress.
Sorry it's so hard!