I have also had deer not leave a blood trail at first and then only a small one after that. It bled internally. I watched the direction it ran off too and waited for about 30 minutes or so before I got down and went tothe spot where I hit her. I found the arrow and walked the line she ran off to and eventually found her. Just b/c there is no trail doesn't mean you didn't kill her. Be patient and spend time looking.
the big 8 i shot with my bow sunday left one drop when i shot him then 15 yards later there was blood spray everywhere for a few yards then real faint then everywhere again... when you lose a blood trail walk a 2 ft. circle around where you last found blood if nothing turns up then go to 3 then 4 just keep looking trying to focus on the way you seen him run.