From your symptoms, you seemed to have developed peripheral vascular disorder.
Peripheral vascular disorder could occur due to many reasons like exposure to cold for a long time is also a possibility. Before that I want you to check your blood sugar, just to rule out diabetes mellitus. Your symptoms of feet being cold all the time suggests you are in verge of developing gangrene.
Gangrene if once occurs, has not much cured other than amputation. You need to prevent that from happening. I suggest you to try keeping your legs warm, by wearing sock till knee and don’t expose to cold. To maintain proper circulation, I suggest you exercise every day, maybe a brisk walk will do for 30 minutes every day. As you don't have any sensation, I suggest you be careful especially if you get hurt or to burn as you will not know and damage your leg even more.
I suggest its better you go to a physician who can check the blood flow with Doppler. And also will tell you if you have developed gangrene.