There is usually something I am trying to avoid, and rather than have to face it, my avoidance is translated into a listless feeling of wanting to stay in bed. Rather than find a constructive way to deal with it, sleep seems to be the easier route. So I avoid taking responsibility by slipping into a state of avoidance, of listlessness. You can't put anything off forever. You will carry that feeling of the 'blah's' until you deal with what is causing you to feel that way.
Unresolved issues are a drain on our energy.
It is as if you have a tube connected to the 'problem' and energy keeps leaking from you until you sever the connection by changing your attitude, taking action, and resolving the issue. So, if you wake up in the morning and feel as if you don't want to get up out of bed, I would suggest you take responsibility for that feeling and ask yourself what it is you are hiding from and then deal with the situation. The avoidance of expected pain or imagined confrontations translates into a mediocre existence lacking in joy and vitality. Your level of vibrancy will be very different when you affirm and practice an enthusiastic and responsive approach to life. Life can be joyful and happy.