pain returns!

I has been eight months since I first broke my leg. I had a tib/fib fracture just able the ankle and a dislocated ankle. I had a plate put in a week later.
I was NWB for six weeks and then went to FWB. I have had some pain, but nothing that I could not stand. I have been wearing an ankle brace because my ankle seems to give out sometimes and other times it feels out of place. My doctor does not think I have ligament damage, but it could be possible. Two days ago, I started getting shooting pains from my ankle to my knee. I have never felt this before. It got so bad that it felt like my leg was going to give out. I bearly could walk. Has anyone had this happen to them? What could it be? I do not know if I should worry or not.