Have you experienced the feeling of being lost, confused and unmotivated to do anything but cannot figure out why?

Lately I feel that I just want to lay in bed and sleep. I don't want to do the things which I used to enjoy or be happy with what I got. I don't know if I am having an identity or mindset crisis or is this a phase of life we go through once as we grow older and realise I am not the same person as yesterday.