How to live in purpose?

I'm feeling quite low...
Unmotivated is the key word.
What the hell am I doing with my life? What the hell do I want to do with my life?

I know that I have a full life in front of me. I do know that I can do whatever I want to do. I am extremely lucky in that I have always had food & shelter and all the chances to have an education. I have always landed good jobs. I have a strong supportive family. I have all the conditions to be happy.

But I just don't seem to be doing something that is motivating. Work is paramount to me. I want to be fulfiled my work.
But I don't know what is it that would fulfil me and give me daily joy.

How do you understand this? How can I discover what I would really want to do?
Can somebody help me?