I just came back from a similar injury. For several weeks I literally coudnt even walk. I would jump around on my other leg and/or grab anything around me for support. Every step on the injured leg would be extremely painful.
All though I was not able to walk for several weeks, I quickly became able to use the bicycle as there is less pressure on the leg here than when walking. I would often cycle 20-40km and see how my legs felt. When there was absolutely no pain or irritation during cycling, I started walking. Then I walked up and down stairs. This was the final test for me and I started running after that (carefully). Carefully means that if you feel any sharp pain from especially the injured area, you stop right away. General pain and irritation is normal if you haven't run for a while, and you have to seperate this from sharp pain. If your feeling pain, ask yourself where it is from? If the pain is from the same injured area, then your definately not ready. There cannot be any pain there when you start again, even if it is small aches from the same area. As a general advice, always pay alot of attention to your your legs while running. You will notice irritation and pains and you'll naturally learn to tell irritation. Still there can be pains that could potentially be very serious, and that you just can't tell from normal pain and irritation. This risk will always be there. One of the things you can do to reduce the risk of such pains occuring, is give your legs some rest (even if you feel absolutely fine). Don't worry, I was scared and worried too about comming back, but it goes away and as you will start to pay more attention to what you feel during runs your confidence in your legs will come back pretty quickly.