Lethargic

I feel lethargic, dont feel like doing anything but just sleep on my bed and rot.
Lots of readings and notes in front of me, yet my brain is wondering away,
I need to focus, i need to build up my momentum
But how?
How can i do it?
It feels so hard, am i pushing myself?
I just feel bad, as if the whole world did wrong to me,
I wish to lock myself in a cave and never go out again.