Feeling demotivated, bored and depressed when I don't have anything to do

By 'anything' I mean important tasks. I'm not sure why I think this way, maybe it's because of some underlying condition but I can't bring myself to focus on stuff unless extremely necessary. If I don't have shit to do I am overcome by this almost suffocating wave of boredom and depression. If I even forced myself to do some fun or relaxing activities I can't bring myself to focus on it. So I waste my time until I have another important task in my hand.

I really need to understand why the fuck I feel this way. Why is my behavior so atypical compared to other people. If another 'normal' person was in my shoes they'd feel relaxed and enjoy their free time.