Firstly, I'm sorry that you are going through this. It's surprising to me that someone so young would have a total knee replacement. If I were you, I would get a 2nd opinion.
Hello!
You can take over the counter pain medications such as ibuprofen and apply ice packs.
Pain will only be relieved by physiotherapy.
Make sure by recent scans that you do not have any complications after surgery. Rule out infections and maintain complete hygiene.
Post operative pain should be relieved after a month from surgery.
Take a second opinion as you had your surgery in 2009.
Take care!
Consider doing some physical therapy to improve your stability and/or get a second opinion?