What Causes Lupus?

Is it possible for me to have lupus or any other deadly disorder or is it just my anxiety? Height 159 cm, weight 69 kg, no fevers only a few hospitalizations I am a 25 year old male. I had chest pains for a few months. The pain usually radiated to my left arm. I went to a cardio doctor and he had me take a chest X-ray and a blood test. He said everything is normal and gave me some medciations that has to do something with digestion I think. The chest pain has gone away now (the radiating left shoulder pain is completely gone but the chest pains a very little at times). However, I got anxiety you could say because of many events, and I was very much worried about my parent s health too. Now I feel sleepy all the time with my eyes kind of burning. I cannot say I am exhuasted but kinda feel sleepy. I also feel like being a fantasy world. Recently I read about the symptoms of lupus and I am worried I may have it? Dunno why I think so but I just think so coz I dont feel brisk anymore and the recent chest pain that got away worries too. The X-ray report came as: Normal heart Normal Aorta Normal Lungs Normal (Something) it was not clearly written The blood test came as: TWBC - 9500 cell/ cubic something Differential count Polyneutrophils: 44% Lymphocytes: 54% Eosinophils – 01% Monocytes – 01% Basophils – Nil Heamoglobin (Sahlis) – 14.4 gms ESR Westergen’s Method ½ hours – 02 mm 1 hour – 05mm He took an ECG and said that nothing to worry in the ECG too except a slightly high heart rate and told me to exercise a lot. I have also have sensations of vomiting immediately after I eat since childhood and my nose is filled with mucus or whatever it is all times Does this by any chance indicate chances of having lupus or any other deadly disease as cancer? Or am I being overreacting and causing anxiety? If the answer is anxiety, I would start to make up my mind. So please someone gimme a detailed answer. I always wonder why the doctor did not order for a platelet count and RBC count