1. You need first to consult a medical doctor and act upon a confirmed medical advice.
2. You need to remember the big losses in this life and hereafter caused by over sleeping.
The Hadeeth says: Beware of over sleeping , as it makes you poor in the Day of Judgment.
3. You need to strengthen your will power to be able to get up on time of prayers and work.
4. Avoid over eating / over drinking liquids, as it causes heaviness and oversleeping.
5. Recite the last verse in Sura Al-Kahf (The Cave) as it helps a lot in getting up when you want. (18:110).