Autoimmune diseases like RA, lupus, diabetes (T1), hashimotos among others, are often found in the families of celiacs, or in celiacs too (many of us have a few issues). Having AI diseases in the family is a good reason to keep an eye on celiac symptoms. I have family members with celiac disease, I also have some with thyroid problems (seems like half of them) and RA too. I have celiac disease, hashi's, and an autoimmune blood disease (ITP) which caused some serious anemia when I was in my late teens(it's not common).
Low cholesterol is common here too. If you search the forum for it you'll probably find a few stories. Mine is low to off the normal range low... Low enough that one doctor has tried to raise it, my old doctor just congratulated me for eating right... yet I was an undiagnosed celiac eating gluten at the time. LOL
The average diet has 10-40g of gluten per day in it. A slice of bread is just under 5g and a (small) serving of pasta is over 6g. A gluten challenge needs about 5-10g of gluten per day, which is technically less than the average person. If you ate enough cookies, you should have been fine for the tests.