Why do you want to eat wheat?

Take the diagnosis and run.  In the worst case you can stop eating gluten free after say a six month trial.  Some, like recovering alcoholics never get over the craving.  Resistance is not futile.  Some wait as much as ten years to finally get the diagnosis.  Be sure to monitor your diet for vitamins and minerals.  During recovery you need way more than the minimum to rebuild.

Malabsorption is a potential complication of bariatric surgery.  Is one your docs monitering vitamin D and other vitamins and mineral? Malabsorption due to the surgery and now adding the malabsorption from Celiac Disease?  Nutrition advice? One hears stories; "You've got Celiac Disease, don't eat gluten.  Have a nice day". Gluten Free stops the ongoing assault, but you need to also work on the deficiencies.  Can't heal without giving your body the tools it needs.  I like your new doctor, he is telling you what you need to hear, not what you want.  Maybe you'll even get to like him. A lot of the mistrust of aspirin, I think was the marketing campaign of Tylanol.  "Nine out of ten hospitals choose..." Try disolving your aspirin in bicarbonate, or cut an Alka Seltzer Original (aspirin with bicarbonate) down to your required dose.  It is disolved so spends no time burning on the stomach floor and the bicarb temporatily nutralizes the stomach HCl.

Welcome to the forum, @RedPandi! I don't know that I'd make too much out of the variation in your reaction to different gluten-containing foods. It could be due to many things including the amount of gluten in different sources, how full or empty your gut is at the time of consumption, the buffering effects of other ingredients on the rate of digestion/absorption and variations in your metabolism at the specific time of consumption. Also, there are different strains of wheat which seem to make a significant difference in how people react to the gluten in foods they are used in. For instance, on this forum we have gotten more than a few anecdotal reports of celiacs traveling to foreign countries and finding they are able to eat items in those countries made from wheat without issue. And more than a few report they can eat sour dough wheat bread without problems. But I do want to make sure you are following the most recent protocols for the gluten challenge since older protocols are still out there on the web and also being propagated by some medical professionals. The current protocols call for the daily consumption of 10g of gluten or more for at least two weeks before getting tested. 10g is about the amount found in 4-6 slices of bread. To be safe, I would go for 4 weeks. You don't want to waste the torture experience.

Vitamin D concentrations <20 ng/mL are associated with a significant increase in the number of eosinophils in blood.    As Scott said, "A weak positive is still a positive".   You could insist on an endoscopy with celiac biopsy.  One day without eating will not effect your blood work.  Weeks or months Gluten free will.  It all depends on the balance of benefits of an official diagnosis to the continued suffering while chasing the diagnosis.   With your long history, including malnutrition and a family history, and the doctors don't know why, let us face it you are fighting a losing battle.  You have Celiac Disease, even if the doctors say no.  Some test negative and are positive biopsy, many on the forum have tested all negative, only to finally be positive up to ten years later. The ultimate test is to follow your family member's lead.  Get gluten out of your life and fix your malnutrition.  Yes it is difficult because we are engulfed in a society that considers wheat sacrosant but once you get over the addiction and clear the residual glutin from your body you will feel so much better.  Just GFD will not be enough.  Celiac Disease causes malabsorption of some twenty vitamins and minerals, explaining your malnutrition.  It is the malnutrition that will kill you.  Starting with your seriously compromised immune system vitamin D, evidenced by your eosiniphil count that the doctors can't account for. Want proof?  Get tested for vitamin D, Thiamine, homocysteine and Urinary Iodine Concentration for starters.  It will show if you are deficient in vitamin D, B1, choline, B12, B6, folate and iodine.  You have to ask for these, doctors don't normally check. You might want to see a dermatologist familiar with dermatitis herpetiformis, dermatitus herpetiformus as it is the dermatological symptom of Celiac Disease.  Many with dermatitis herpetiformis are seronegative and biopsy negative.  Some with dermatitis herpetiformis find that iodine can exasperate the breakouts so worth testing for.  The biopsy has to be taken in clear skin, near the pustules, not like other derm biopsies, so you need to find a dermatologist familiar with the procedure. Here is an odd symptom I had.  I wear contact lenses (since 1972) and I always had to take them out every two weeks to clean "protein build up".  Not long after starting GFD at age 63, no more protein buildup.  I go on average 6 months now without taking them out.  Fibromyalgia gone.  I am pretty sure the gluten was incorporated in muscle and joints and was being attacked by the out of control T and B cells (not enough vitamin D to control them). Can I prove it? No, but I no longer have pain. That's some kind of proof. I am sorry if it sounds like bad news; but you'll thank me later.