That's interesting because I think that the lousy 81 mg irritates my gut. I'm sensitive to drugs in general and blood thinners are all the same to me so aspirin necessary evil. As they say, better to be a live chicken than a dead duck. 

I've been using a Brita water filter for well over a decade without any issues. I seriously doubt that these water filter companies would use glues that would end up in your water, as that would be counter to what they are trying to do, which is to purify tap water. Please provide some specific evidence to back this claim up, as such speculation can cause undo fear, as well as reputational damage to these companies. Don't get me wrong here, I am not saying that this isn't possible, but is very unlikely.

Welcome to the forum, @aperlo34! You said you had a colonoscopy "ordered" in July? Has that procedure happened yet? A colonoscopy cannot be used to diagnose celiac disease so I assume the order for the colonoscopy is to check for something else. The procedure used to diagnose celiac disease is the endoscopy. So, I assume you have had blood antibody testing done and it was positive and then you had an endoscopy/biopsy done to confirm those results? That is the normal process for diagnosing celiac disease. Have your constipation/irregularity problems improved since going gluten free? Some of the continuing symptoms you describe would seem to fall into the category of neurological effects (muscle twitching, shakiness, weakness and headaches) and others such as dry eyes, fatigue, stiffness and joint aches sound like they could be autoimmune effects. Are you taking any high potency to vitamin and mineral supplements? Celiac disease often/typically results in vitamin and mineral deficiencies due to malabsorption from the damage to the small bowel lining it causes. I note that your vitamin D levels are barely within normal range and the only B vitamin testes is B12. The B vitamins and D3 are very important to neurological health. And the several B vitamins all work together synergistically. So, they all need to be up to snuff, not just B12. I would suggest starting on D3 supplementation in the amount of about 5000 IU daily and also a high potency B-complex. Costco's Nature Made and Kirkland brand products are good quality and priced well and usually gluten free (and will state so on the packaging). Realize also that gluten free flours and facsimile foods are not fortified as are their FDA mandated gluten equivalents. So, when you cut out gluten, you cut out a significant source of vitamins. One thing to be aware of is that Celiac disease is an autoimmune disorder and autoimmune disorders tend to cluster. That is, when you have one you there is a good chance you will develop others in time. I don't wish to alarm you because I know you have said you already struggle with heath anxiety but many of your symptoms make me think you have some other autoimmune condition going on in addition to celiac disease. Have you been checked for Sjogren's or lupus for instance?  Finally, I am including an article that is helpful to newly diagnosed celiacs in getting a head start on the learning curve of eating gluten free:   

This article may also be helpful as it offers various ways to relieve the itch:  

The most common nutrient deficiencies associated with celiac disease that may lead to testing for the condition include iron, vitamin D, folate (vitamin B9), vitamin B12, calcium, zinc, and magnesium.  Unfortunately many doctors, including my own doctor at the time, don't do extensive follow up testing for a broad range of nutrient deficiencies, nor recommend that those just diagnosed with celiac disease take a broad spectrum vitamin/mineral supplement, which would greatly benefit most, if not all, newly diagnosed celiacs. Because of this it took me decades to overcome a few long-standing issues I had that were associated with gluten ataxia, for example numbness and tingling in my feet, and muscle knots--especially in my shoulders an neck. Only long term extensive supplementation has helped me to resolve these issues.