Best to see a nephrologist if you suspect kidney involvement. I had it and diagnosis was confirmed by a biopsy. Meds got things under control and I have been fine for 11 years and I will continue to take them forever at low doses.
Link that gives information about LN with a short list of symptoms.
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.