I Have Just Had A Total Knee Replacement Almost 6

I have just had a total knee replacement almost 6 weeks. Only on standing my knee swells and I get a discoluration of red/purple as soon as I elevate it goes back to normal colour. I'm not due for my follow up with my surgeon until another week. I have had a blood test for Crp and that all came back normal. I'm worried is this just a part of the healing process