With the amount of blood you say he lost, its possible or likely he won't survive. One lung hits can go a LONG way, and a long time. Sometimes even survive, depending on the hit. I would say either get a dog to help you track, or start looking for buzzards and grid searching. Better to recover him late, than not at all.
Turns out waiting 5.5hrs was definitely a good decision, especially given that you thought you had a good hit. I doubt most would have waited nearly that long in reality. Its easy to rethink it all later and decide what would have been the best thing to do. Did you find any big pools or beds?
I killed one like that once... it turned right as I shot and I only got one lung. Luckily for me, it only went 40-50yds and bedded down. Took him right at 3hrs to die - I was pinned in the tree, no way to get down and no way to get another shot. That sucked but at least I got him. No doubt I would have pushed him a long way had I gotten down.