Hi Eric
Your on a totally different level of 'awesomeness'; showing incredible perseverance and determination; keep being positive, things will get better.
Could this be the reason that your losing fluids; there isn't enough small bowel to absorb the water?
'removed my entire colon and most of my small bowel, leaving me with only approximately 5-10% of my entire GI tract'
Also not great, but nutritional drinks might be the way forward; I'm talking about a few months. That might help to build yourself up.