Without getting too specific, it sounds like you hit her near the spine- enough to shock her and knock her down, but you gave her time to recover. I have seen this scenario twice firsthand- once myself, and once with a friend I was with. Both times with muzzleloaders shooting round ball. There was enough shock to initiate a good bleed at first, and knock the deer down. I quickly reloaded and finished my deer, the other my buddy coudlnt get to his reload, and by the time I got to him (five-8 minutes) it had recovered enough to drag itself into some heavy cover where it recovered enough to run off. We followed for 1/2 mile and 3 hrs, lost it in the rain.