Suggest Treatment For Severe Pain In The Knee Post Surgery

my right knee is in pain had falls I had surgery 6 weeks ago arthroscopic but still draining fluid this is the 7th time fluid has been drained and I can t even go up stairs or walk hardly now he says I have arthritus now I had blood drawn today for ser and other things I guess and he said I need a full knee replacement but I am 41 too young but I hurt and can t move it why is he taking my blood and what can I do I can t live like this