If I had to guess what happened, I would only guess that the deer was shot through that part of the body where there are no vital organs end and pure muscle tissue begin. These are located above the lungs under the spine (I have seen them run a long way and hardly if any blood), or you shot it through the diaphragm. Sometimes when they are shot through the diaphragm, they take a good hit, but bleed very little. They will run off, then lay down. If you push them they will run again until they can no longer fill their lungs with air. When you locate them, they usually have a large foam bubble from their nose and lungs where they simply suffocated. I took one last year with a bow that way. It tried to duck the arrow.

Due to the powerful load you were shooting it would still knock them off their feet, which you observed. Once they get their senses back, they take off like their tails on fire.

I used to be real meat greedy and never shot for the front shoulder. Now that I have gotten old, I put it through that front shoulder, into the heart and lungs and break them down. I don't like tracking anymore then I have to, and I hate dragging even worse.

Better luck next time. I know the feeling your going through when you hit one hard and then can't find it. I guess that's why its called hunting and not shooting.....