RE: Hit One, Tracking, NEED INPUT
Keep on the bloodtrail just as long as you can. That deer is probably dead from what you describe, but he may have been thinking well enough to attempt to throw you off by backtracking. Decypher that, and get on the trail.
Don't worry if the blood dries up. That's about 30-50 yds from where you find a lot of them.
When he made that P shape, he may have been trying to find a vantage point above his trail, to bed down and watch what was trailing him. He may be dead in that bed. Look for a good vantage point or some thicker cover, blowdown, whatever, above that trail and he may be in it. You mentioned a pond. If all else fails, I would make a bunch of swings through the area between the end of the trail and the pond. He may have been making his way to water. Look in the water too. We reovered one that got in the water and died, all we saw was an ear until we got right to it.
Keep at it. Seriously, sometimes it just takes a while. If all else fails, do the grid thing.