Hi LorenzoMom and welcome to the board!
First off, you can have Lupus without the positive test results. In some people, the blood won't show up when the person is having symptoms! Also, there are 5% of people out there that have Lupus but have never had the positive test results. By looking at your symptoms, it seems that you do have ones that are consistant with Lupus or something autoimmune for sure. Some GP's do blame symptoms on stress or "depression" when they can't figure out the cause. There are lots of markers in the blood and in the urine that can show when Lupus is suspected. These are some:
Lymphopenia- The decrease of lymphocytes in the blood
Urine Protein- The increase of protein in the urine can be a marker
Increased ESR and decreased CRP- Sometimes the ESR will be elevated when there is inflammation in the body.. it is a nonspecific marker for inflammation. The CRP (C-reactive protein) can be very low when the ESR is elevated in people with Lupus. Sometimes my CRP will be 1 and my ESR will be 30!
B12 deficiency- can go with Lupus (Pernicious anemia)
Iron anemia- is another clue that something autoimmune disease is going on
X-rays- showing joint inflammation
History of kidney inflammation
Also, do you have a history of autoimmune diseases in your family? Like Rheumatoid Arthritis, Type 1 Diabetes, Hashimotos Thyroid, Lupus, Crohn's Disease etc
Sampy is correct that you should be tested for Antiphospholipid Syndrome as well. Do you have a history of miscarraige, stroke, TIA (mini stroke), DVT (leg clots) etc. If you do and have migraines then you should get this GP to test you. The blood tests are the anticardiolipin and the Lupus anticoagulant.
Also! I just thought of something else here.
Have you been tested for Sjogren's Syndrome? It is a syndrome that can go with Lupus or occur on its own. It involves dry eyes, dry mouth and nose and dry "woman areas" etc Anything that can get dry does. The test can be quite simple- it can be a piece of litmus paper inserted in the eye to measure the moisture. If it is "bone dry" then you have Sjogren's! ANd if you have Sjogrens, chances are that you have Lupus. I will try and think if there are any more markers in the blood here. Please check out the "Criteria to diagnose Lupus" in this forum. I had to travel to London England to Dr. Hughes to be diagnosed properly becauase Lupus can be so hard to get diagnosed! I hope that you can be referred to a Rheumatologist that specializes in Lupus patients. If your GP continues to blame everything on stress, I think that you need a new one! GP's are our first defence when we have Lupus, they are our saving grace and our biggest advocate. Hope this helps you and that you feel better soon!