Most doctors will diagnose lupus on the basis of clinical symptoms and labs. Often the diagnosis is not clear but if you truly have lupus eventually it will be confirmed in both symptoms and labs. Your rheumy will know what tests to do. Typically cbc, cmp, sed rate (esr), and possibly a lupus panel. Other tests like ultrasound to see if there is any organ involvement can also be ordered if that is suspected.
As for treatment, lupus is usually treatable but some cases are more severe and others just stubborn and chronic. Many patients go through various meds/treatments to find what works for them and carry on a normal life. Others have a problem finding the right treatment for them. Lupus is no different than other autoimmune diseases in these respects.
Remain optimistic and take things a day at a time. Hopefully, your case will be diagnosed and respond well to treatment. I had a very severe life threatening case but have been in full remission for 8 years and off all controlling meds for 3. Each of us is different so all any of us can do is tell you our experiences and what we have heard from others.
MCTD (SLE Lupus, polymyositis, scleroderma). Diagnosed 2005. Kidney, liver, GI tract, dysphagia, raynauds, barretts esophagus, quadriplegic in 2005. Recovered and now active in downhill skiing, golf, hiking. Meds: amlodipine, benezapril, omeprazole, potassium, folic acid, vitamins, maxide.
Remain Optimistic and you can overcome.