I feel sleepy during the day
It is important to differentiate sleepiness from tiredness. When we feel sleepy, it is a conscious struggle to remain awake. On the other hand, when we are tired, we may feel fatigued but still remain relatively alert. You could think about this distinction by associating tiredness as a physical symptom experienced in the muscles in our body. Sleepiness however, is more like 'brain tiredness'.
It's a good idea to try to keep all your sleep for night-time, so if you feel mildly sleepy during the day do your best to counteract it. Exercise at lunchtime can be a good idea – a brisk walk perhaps. Getting out in the daylight is very important because natural light helps keep us alert. Then caffeinated drinks can also give us a much-needed 'boost' during daytime lulls.
The course helps to restore normal levels of sleepiness by increasing sleep pressure – This is a good thing and can be more pronounced during the course, which helps to get your sleep into shape. Often prior to the course, poor sleepers don't feel sleepy at all, night or day! Sleepiness will wear off as your sleep continues to evolve.
However if you feel very sleepy – so sleepy that you might fall asleep without warning – you should take it seriously as it can be dangerous, particularly when driving. In this case you should seek advice from your doctor as soon as possible.