DSPS (delayed sleep phase syndrome) is a tendency to wake up later and later each day. The chief cause of modern DSPS epidemic in youth is the use of electronic devices before sleep, electric lighting, evening socializing, and simply going to sleep too late. Insufficient morning sunlight is also a contributing factor.
If you suffer from a severe case, you can still remedy DSPS without the need to see your doctor. See: Curing DSPS