Confused!!!!!!!!!!!!

Do you ever get depressed for no reason? It's been happening to me quiet often over the past few months. I think I've figured it out. I'm in the midst of a mid life crisis - far too early I might add. I'm dead serious. I've been so confused by life. I've realized I really don't know what I want to do with my life. I'm terrible at sciences and math, yet that's what I decided to go into. I'm not enjoying it. If this was something I wanted to be doing with the rest of my life I think I would be more interested in my classes. But I'm not. I'm not interested and I'm not enjoying school. Every professor I've had has said you might think you know what you want to do, but most students end up changing their mind. I was never completely set on psych nursing, but it seemed like a reasonable option at the time. And my family was proud and happy with that option. That's why I'm so unsure about everything. My real passion is music. I know my chances of ever becoming famous is about one in one hundred billion, but I would LOVE to do something, anything with music. I really can't live without it. If I don't have my iPody  in, I'm singing in my head, or out loud (depending on the situation). I know it's not a very practical choice though. There are so many inspiring music teachers out there because it's one of the few options people have to work with music. Recording studio maybe? But there are so many programs that let you do that from home now. I'm torn between doing something I'm passionate and in love with that may not get me very far, or something practical. Something like nursing or counselling (except I have no life experience) where I'll have a secure job and will be helping people. My family will support me with whatever I do but I don't want to be that slacker kid that takes the easy way out. I'm lazy for sure, but that's not the reason I'm changing my mind. Ah, I feel so lost. I wish I could pause time and figure things out.