I had a sever crush to my ankle by road roller got xray nothing broke it was swollen three times its size but 2 weeks later its still quite swollen?

Soft tissue injury. You should really consult orthopedic physician. Ligamentous injury can be debilitating. With physical exam and usually mr exam exact location of injury can be detected and options for remedying symptoms can be explored. Sometimes ankle joint effusion also contributes to swelling.
Time. If you are able to walk without increasing pain, from initial injury, then it will take time for the swelling to decrease. Use ice to the swelling and elevated the leg several times a day if possible. If you have increasing pain and it is harder to walk go see your doctor for a repeat X-ray, some fractures can not be seen on initial exam.
Sprain. Sounds like a bad sprain which is a tear in the supportive tendons of your ankle. Even though its not broken you should still be wearing a boot that limits the joints mobility in order for the tear to heal and should be limiting your activity as well. The swelling can be normal and will take time resolve. Go see your doctor and try to stay off it till then. .