Hi hellass, I've been having issues around poor digestion lately too and been reading about things like coeliac and similar conditions. Are you demonstrating any other symptoms that are suggestive of coeliac disease? For example if you are having diarrhoea/constipation/bad wind, then I think a doctor would see fit to help you.
You probably know that gluten is contained in crops like wheat, barley, rye (and something very similar in oats) - foods that have been consumed by very few humans before 10,000 years ago.
Estimates are that just under 1% of people have coeliac disease while about 3 or 4% have gluten sensitivity. Coeliac disease involves gluten sensitivity coupled with damaged intestinal vili, making absorption of nutrients very difficult for their body.
Testing for coeliac goes something like this: 5 genetic markers are sought and possession of certain genes give statistically higher likelihoods that you may develop coeliac disease. If the genetic testing suggests coeliac, then they look at your bowel with an endoscope (camera). The endoscopy will give imges of the vili so the doctor can see whether they are healthy or damaged. In the case of a negative genetic result, if the symptoms are overwhelmingly indicative of coeliac then the endoscopy may still be carried out. It is the endoscopy which is the true gold badge of coeliac. (But you need to be consuming gluten for 6 weeks before the endoscopy).
You may try a gluten free diet for at least 2 weeks to see how you get on. If you find your symptoms relieving after some time (many weeks, months) being gluten-free, then you discovered that you are at least gluten-sensitive.
The tests are expensive and that is why no doctor will run them without good reason and long-standing symptoms.
The symptoms of coeliac are really varied and some sufferers show few symptoms. Certainly if you have reason to check this out then do check it out. But don't be too hasty as doctors don't like to feel as though their time is being wasted so be careful about going based on the one very recent symptom you told us (weight loss in one month). Good luck and hope it works out the best for you.