Sounds like you have an overlapping connective tissue disease which includes symptoms of lupus. It is common for this type of disease to develop over time...until then uctd. It makes little difference as the treatment will be the same in most cases. These diagnoses are not easy and sometimes take years to confirm.
One of the diseases will usually become the primary one. I have mctd which is lupus, sclerodrema and polymyositis. Lupus started it and PM became the dominant symptoms. Have very little with scleroderma fortunately. It took about 14 months from the first tests to determine it was mctd which is defined by the anti rnp antibody. However, my docs thought for some time I had it so it was just a confirmation.
MCTD (lupus, scleroderma, polymyositis). Diagnosed 2005. Kidney, liver, GI tract, dysphagia, raynauds, Barretts esophagus, quadriplegic in 2005. Recovered and now active in skiing, tai, chi, hiking, golf. Meds: prednisone 2.5mg, imuran 25mg, amlodipine, benazapril, omeprazole, potassium, folic acid, vitamins, maxide and various supplements and vitamins.
Remain optimistic and you can overcome the odds.