Hi PASC. You and I have MANY of the same symptoms. I have lost almost 20 lbs. in the last few months. I am tired all the time, rarely sleep more than 3 to 4 hrs. a night, and stomach always feels lousy. I rarely get headaches however.
I had a colonoscopy 3 days ago, and they found diverticula. They have put me on antibiotics for 10 days in case of bacterial infection. Have you had this exam yet? They decided I needed it when my bowel habits started to change like you, was going 2 or 3 times a day, then turned to diarrhea every day.
I have had IBS-D for MANY years, but the gastro doesnt think that is my problem this time. There are so many alike symptoms for these digestive disorders, its really hard to know which one is the culprit. Please dont take this the wrong way, as I am VERY sorry you are having problems, but I was almost relieved when I read your post, and realized I was not alone is these symptoms. Please let us know how you are doing, and what your gp decides.
By the way, all my other tests (blood) came out fine too!
Good Luck! Catlover