Gluten free food is not fortified with vitamins and minerals as regular food is.  Vitamin deficiencies are common especially in recently diagnosed persons,  Get a 25(OH)Vitamin D blood test. And work on raising it.  The safe upper blood level is around 200 nmol/L.    "Low serum levels of 25(OH)D have been associated with increased risk of autoimmune disease onset and/or high disease activity. The role of vitamin D in autoimmune diseases   🏋️‍♂️Good job!   I find the commercial milk will give me mild stomach burn at night, while pasture/grassfed only milk does not bother me at all.  While you are healing, listen to your body.  If it hurts to eat something, eat something else.  You may be able to eat it later, or maybe it is just not good for you.  Lower your Omega 6 to 3 ratio of what you eat.  Most omega 6 fatty acids are inflammation causing.    The standard american diet omega 6:3 ratio is estimated at upward of 14:1.  Thats why fish oil works

I  notice a reaction to tea bags, possibly due to gluten or other substances. Is this recognizable?

The blood tests you had done are not the main ones. The two main ones are the "Total IGA" (to check for IGA deficiency) and the "TTG-IGA". Current guidelines for the "gluten challenge" when people have been gluten free for a significant time period are the daily consumption of at least10g of gluten (about the amount in 4-6 slices of wheat bread) for at least two weeks leading up to the day of the blood draw. That should give you some perspective.

Thank you, really.  I took a test for DGP-IgA and DGP-IgG. Effectively, it is not enough to discard Celiac Disease. I was consuming gluten until then, I only started gluten-free some days ago, when the symptoms became horrible and now I feel considerably better, which is a second confirmation that gluten is the main problem. It's been more than 4 years I have the same suspect, when I first thought gluten was causing me problems, I made a gluten-free diet for a year, I felt really good as never before. However, neither I or my parents were well informed about Celiac disease, so none of us tried to make further exams. My father suffer digestive problems and other members of my family as well. Unfortunately, no one have ever been tested for Celiac disease. I'll have to restart eating gluten in the next weeks, so I can make a serious blood test in laboratory, hopefully between two or three months.

As Scott said, in order for celiac disease testing to be valid, you need to be eating generous amounts of gluten on a regular basis for weeks or months before the blood draw. The blood tests are designed to detect antibodies that the immune system produces in response to the ingestion of gluten. It takes time for them to build up in the blood to detectable levels.