Abnormal condition causes underweight issues. Please Help me

Patient: My metabolism is very, very, very high. I have tested many combination’s of healthy,unhealthy eating habits ranging from 2000 to 6000 calories a day, while also testing the effects during months of weekly workout regimens and months of no physical activity. I currently weigh 145 lbs and the most I have ever weighed was 155 lbs. I fluctuate between 140 and 155 constantly. I know and am told constantly that I must simply take in more calories than I burn off but no one ever takes the time to access my outside deli-ma. My kidney’s while functioning in every other form, are medically failing at the processing of proteins. My test show that I process 400% less protein than an average male and as I increase my protein intake, my percentage degrades. So with my inability to process protein in conjunction with my extreme metabolism has put my body in a unhealthy state of weight. I am underweight as I am 6’6″ and 145 lbs. Please help me get my body’s health back on track. I want to be normal and weigh at least 180 lbs.