I broke both tibia ad fibula just above the ankle joint and dislocated my ankle. Surgery three months ago fixed the bones with a plate and five screws in one and three screws in the other. I still cannot bear weight on the affected foot and when I try I g

Healed? I suspect if you still can't bear weight that the bones have not healed or have shifted in a way that causes pain. You need to see your orthopaedic surgeon for x-rays and an evaluation. Make sure they review your injury and the current state o healing with you.
May take longer. Obviously you sustained a severe injury to your ankle. Once the doctor confirms that the fracture is healed sufficiently you will be allowed and be able to weighbear on the ankle. Hopefully you are not getting a delayed or nonunion in the area.
Talk to your doctor. This needs further evaluation. Talk to your doctor.