Most of the people who are not in a habit of waking up early try to persuade themselves that they need more sleep. As and when you get up and are still under the influence of a hangover, your mind says that you need to sleep again.
Though you are fully convinced that you should wake up early and for that you have made an effort. However your inner self wants you to sleep again and for this your brain gives lot of arguments. A thought would come to you that you should have a nap of another ten minutes as that would make no difference in getting up from the bed. Another suggestion would come from the mind that since you have not slept well at night, so you need some more sleep, or since you are going to have a very busy day ahead that is going to make you tired, you therefore need another one-hour sleep, so that you get up more fresh and in high spirit.
A tussle will start between you and your mind. It has to be seen who wins at the end. Obviously you want to win and do not want to sleep in. Then how to ensure your success in this battle? The best way is to avoid any reasoning with your mind. Do not think much about the advantages and disadvantages of a sleep in. Just jump out of the bed and get into some task. Make yourself busy so that you do not even think about sleeping again. Moreover, the physical and mental activity that you are involved in, will make you fresh and active.
Actually your weakness is the desire to go to sleep again. Try to overcome your weakness with the help of a strong urge to remain awake. With practice you will be successful.