Coeliac disease (gluten intolerance) is another autoimmune disorder that has a similar genetic predisposition as lupus (its not directly inherited, but it does run in families who also have RA, lupus, some thyroid problems, etc).
If you are gluten intolerant, then you really do need to get it medically diagnosed, so that you get the right advice about remaining TOTALLY gluten free, not just low gluten which is what will happen if you try and do it yourself - there is just so much hidden gluten in foods. If you have coeliac disease, then a gluten free diet for the rest of your life is essential to avoid further problems (which can include coeliac neuropathy as well as malabsorption problems etc).
The only problem is that you cannot get it medically diagnosed while you are actually on a gluten free diet. I really despair of nutritionists and alternative health practitioners who suggest gluten free diets without you getting properly tested (you need blood tests first, then if those are positive you have to have an endoscopy and biopsy to confirm it). The only way you are now going to get it confirmed is to go back onto a full gluten containing diet for at least six weeks, which will probably make you feel awful again.
You could just continue as you are - limiting gluten and feeling a bit better. It probably won't last though. For a start, without a proper diagnosis you won't have the incentive to remain totally gluten free so will start sneaking in little bits, especially when you are out and it seems too hard to bother. For a coeliac, as little as one gluten dose every month can keep your body in a bad way and negate the rest of the month being gluten free. I have known many people who put themselves on a GF diet, which had the same wonderful results as you initially, but then because they didn't realise they were getting hidden gluten, or they started taking in a bit of rye or barley (which also contain gluten), gradually they deteriorated again. Their response was to say that the GF diet didn't work, when really they weren't on a totally GF diet.
My advice to you now would be to go back onto a full Gluten containing diet (equivalent to 2-4 slices of bread a day) for at least six weeks, then go back to your GP and insist on being checked (blood tests initially) for coeliac disease. You may have to argue a bit on this as most GPs are really unaware of coeliac disease, but at least now you know that a GF diet does make you feel better. Read up the information pages from the
www.coeliacuk.org.uk website first to get more information yourself (they have a downloadable leaflet about what to do if you suspect coeliac).
The good news is that if you do get it diagnosed properly, then you will be eligible for prescribable gluten free food, which will make it a lot easier to adhere to the diet.