Thanks for your query at Spring Health
Your complaints of nausea, pain in lower back and swollen left leg points out to be glomerulonephritis.
Glomerulonephritis is inflammation of the kidney, it can occur as a primary disease or associated with other disorders like diabetes. Few tests have to be done to confirm the diagnosis like abdominal CT, ultrasound of kidney, IVP, urine creatinine, creatinine clearance, specific gravity of urine.
Firstly, the blood pressure has to be controlled with captopril, you will also have to take corticosteroids, before all that I suggest you take less salt in your diet and exercise daily. plasmapheresis, a procedure may be required in some cases.
Hope this helps. Please feel free to ask follow-up questions