You go to Stage Four when you finally awake. Stage Five is the deepest sleep you will ever go to. It is similar to being in a coma, except that you are not really awake. It is believed by many people that you pass out from Stage Five into Stage Six - the lighter sleep stage.
If you have been sleeping for five or six hours, then you are in Stage One. You will experience four or five of the different stages listed above, including the dream. Stage One only lasts for a few days and after that, you will return to being yourself again. If you have been sleeping for seven or eight hours, you are in Stage Two. You will go through all of the four or five stages listed, but at this point, you will also be experiencing amnesia and will not remember anything of the dream.
After you experience all of the stages listed above, you will go through a light sleep, which means you will be extremely sleepy the whole night. Your body will wake up at this point and you will have difficulty waking up. When you finally awake, you will be extremely tired and your memory will be fuzzy.