I would think that you hit the shoulder..Deer have a lot more blood than you think. I would go to were you last found blood and start making circles around it looking for the deer/blood. Make small circles at first then go to bigger circles.. IS their water anywhere? If so it might have headed into that direction.Did the arrow Break? IF it broke it might have got inside the cavity. If not your probably going to have trouble finding her. I wish you the best of luck i know how much it sucks to lose a blood Trail