Stomach/bowel issues and doctors are clueless

First background, my stomach isssues started and I figured it was just my IBS-D flaring up so I did what I usually do and cut out all triggers. Cut to 5 years later I have been diagnosed with Fibromyalgia, arthritis, kidney disease, an iron and magnesium deficiency, Hashimotos, I still technically have IBS-D and have had anxiety and depression disorders or years as well. My stomach issues are still AWFUL, my GI doctor says it’s just the IBS but my rheumatologist says it’s colitis but there’s no “proof” except for my symptoms and the arthritis. I can’t eat anything without being nauseous and having diarrhea, I go ten or more times a day. Also for more background I do not sleep because of the fibromyalgia or whatever, and my gallbladder is so-so according to test, my pancreas and liver are “okay” but not great. I’m very much into eating whole foods and fresh fruits, veggies, not muched processed stuff but I can’t eat any of it. I’m basically living off of toast, cream of wheat, applesauce, plain chicken breast, and potatoes. Once my doctors said “colitis” I tried to work in very cooked veggies and different fruits, and some days it’s okay but usually I pay for it. On the “good days” I can have cooked string beans, carrots and spinach. Peaches, mango and mandarin orange cups, and eggs. No dairy, no grains, nothing fresh. Okay so now my question is, has anyone else had this and what do they have!? Or could it be an extreme form of colitis and this is just how it is? Any new information would be great. And just so some know, I have tried fifty different things, such as juicing, smoothies, supplements, teas, etc. 

I'm surprised your Rheumatologist suggesting you have colitis. I would have thought this was the job of your gastroenterologist to diagnose this since intestinal complaints come under gastroenterology.  To find out if you have colitis, ask for a fecal calprotectin test.  If your level is very high,  this would suggest inflammation and you would be referred for a colonoscopy to confirm IBD (colitis/microscopic colitis/crohns).  If the calprotectin test is low, it would suggest that you don't have IBD and it is more likely to be IBS.

My gastrointestinal doctor ran those test already and said they were all negative, I’ve had a lot of test and they’re all negative that’s why he said he believes it to be just IBS-D. My rheumatologist suggested colitis because of the form of arthritis I have, and he tends to look at my body as a “whole” rather than just one part, which I like about him. I’ve had IBS-D since I was 21 (I’m now 33) and had many flares and remissions but this isn’t anything like any IBS flare I’ve had. Once the other doctor suggested colitis I went on a “colitis diet” which seemed to help at first but now I’m back to not being able to eat anything again. Even foods that normally don’t bother me too much, I can’t tolerate. I get nauseated and have to run to the bathroom. I was hoping someone on here had a similar experience and may have had some ideas. 

Believe and trust your gastroenterologist because the calprotectin test is very accurate and if it was negative, this means that you don’t have IBD.  If you don’t have bleeding or severe weight loss then you are unlikely to have it.  However, anxiety can also cause weight loss.

Your symptoms sound like a classic IBS flare up and it is common for people to say that their recent flare up was far worse than any other they have experienced.  Foods that affect you one week will not affect you the following week.  Medications can be effective for a while can suddenly stop working   Anxiety will increase flare ups and will make them more severe.  Fibromyalagia may also be making your IBS worse too.The other conditions you have mentioned could also be contributing to your IBS.

People with Fibromyalagia often have IBS as well.  IBS is very unpredictable and everyone has their own individual IBS.  Symptoms vary with sufferers.

Try bananas or rice to bind you up or try Imodium which really works for me if my IBS gives me diarrhoea.  In the main, I have IBS C.  Have you tried Low Fodmap?

If you are still concerned, ask your gastroenterologist about Bile Acid Malabsorption which causes diarrhoea and can be confused with IBS D. A SECHAT scan would pick it up and there is treatment if you have it.