I get mild headache most of times these days and It's difficult to keep awake. This leads to sleep during daytime and very difficult to awake. I am irritated due to this specially when asked to think about, read or calculate something. This is not a recent issue and I have experienced it earlier as well, few years back. I have been ignoring this for long but now I am thinking to get this examined as it is hitting my abilities drastically. What could be the possible reasons and way ahead?