It is impossible to say where you hit it, but I really doubt that a vital hit could have all the blood wiped clean. Because you found "fat, hair, and flesh" it really sounds like a "flesh wound." However, I would give him several hours and then search for him like crazy. Follow all trails leading in and out of the thick stuff. If there is water, go up and down both sides of it.
However, the way a broadhead cuts, I don't think it was a fatal shot if there was no blood.
Good luck, and if he is down I hope you find him.