Of course lupus is regularly misdiagnosed. My aunt has it for 10 years. First they thought its rheumatoid arthritis, for she had all those swelling and discomfort in the joints. But no treatments worked that time. Then she had that red rash on her face and they finally found out it was lupus. Not that longer than you, but still took them four months. Now she is battling lupus and dealing with the rashes, severe headaches, joint pain, mild strokes, you name it. But I guess her condition is not that bad, as long as her takes enough rest.