I am a lark, but sometimes it is easy to stay awake past midnight. the problem is, no matter when i go to bed, i always wake up at 5-6am... why?!

Sleep hygene: If this has been going on for years, it might just be your body's natural cycle. However, you can try a few things to re-set your internal clock. First, do not read or watch TV in bed. Do not smoke or drink coffee within 6 hours of going to bed. go to bed at the same time every night. Get at least 30 minutes of exercise daily, but not within 3 hours of going to bed. You can try melatonin.