I Have A Right ATK Amputation, 13 Years Ago. I

I have a right ATK amputation, 13 years ago. I lately have been experiencing Sevier swelling in my left leg, stomache, and groin areas. I am on lasics 120 mg a day, and was inpatient for 16 days the beginning of this month for IV lasics. I have been out of the hosp. for 7 days, and found out this morning I have gained 70 pounds. They suggest take more lasics. I say there must be a root problem causing the swelling.. Any ideas?