I want to take a 5 hour nap.
Why do you want to nap for that long.
I feel very tired.
Five hours is too long for a nap especially if you have things to get done. If you nap for that long you will ruin your sleep cycle because you won't be able to get to sleep at night. Take a short nap if you're tired, about a half hour or hour is enough.
I don't think a 1-2 hour nap will do it for me.
Well, sleeping too long will mess up your sleeping pattern and prevent you from getting stuff done. Try the 1-2 hour nap and see if that helps you.