I have been where you at now.ABSOLUTLEY-do not practice at 4-5 hours at a time.as you found out,you tire easily.When ya get tired it affects everything.I shoot 12 arrows-then quit for 30min or so-then 12 more.Your trying to rush musle buildup,etc.The previus post have great info for ya.Also if your going to hunt-practice wearing a jacket youd wear&practice when its cold outside.Colder weather affects you also.Good luck