How do I discover my true passion for life?

I am not sure what my true passion in life is (I am 25, and feel am wasting my time). I am already a nurse - I love it, as I get to see many different people and help them too - But I feel as if I am at a point where I want a change. I don't have many friends left - And the one friend who is supposed to be my best friend is suddenly acting distant. Has anyone experienced what I am going through, and is it normal for me to question what it is I really want out of life? I don't feel a sense of stability - Hence this is why I am so confused with myself.