Confused again, what's new?

I have no idea what I want to do with my life. I keep changing my mind, basically on a daily basis, about what I love and what I want to fill my life with. I thought that I was going to college to get on track to do something I care about, but everything I learn keeps confusing me and makes me wonder if I will ever figure any of it out. I thought I really loved Psychology, but I don't feel like I am learning very much in my Psychology class. I am good at math, and I enjoy figuring out problems, but if that is what I decide to do with my life, I might as well quit college and let my boss pay for the actuarial classes she wants me to take. I love my Arts and Ideas class, it makes me think like crazy, but what on earth can I do with it? I could read a lot and drive myself insane thinking about big issues all the time. But I can do that without a degree and it doesn't exactly pay the rent to sit around and read great authors all day. Anyway, we talked about Othello last night in class. The book is full of characters who have no idea who the others are. We were discussing how people can determine who other people really are. I feel like you really can't know who anyone else truly is, and it is hard to really even know yourself. This is for a number of reasons. First of all, who you are changes constantly. I am definitely not the same person that I was five years ago, or even one year ago. Best case scenario, you are constantly working on yourself and improving yourself, learning from all the experiences that happen in your life. Worst case scenario being that you are going downhill. No one can stay the same forever, life has to have some effect. A friend of mine likened life to a fish swimming upstream, if you are not working hard to make progress, you are flying backwards. But I think it is hard to know who someone really is for another reason. We play different roles depending on what setting we are in. When I am with my family, I am a totally different person than when I am with my friends. And when I am with my friends, I am a completely different person than when I am at school. In a lot of ways, this is unconscious. Throughout life, we teach ourselves that different people expect different things from us, and we play to those expectations. When I was younger, I learned that smart girls intimidate guys, so I taught myself to act dumb when I was on dates. Today, that is not the image that I necessarily want to project, but because I ingrained it in myself, I have a very hard time letting my intellect show through when I am around a guy that I like. How do we figure out which persona is our real self? I don't know. I guess that is why I am having so much trouble figuring out what I really want to do with my life. Depending on the setting I am in, and the focus I have at the moment, I enjoy different things and want different things to be the center of my life. How do I find out what really cuts to the core of who I am, what I really want to focus on for the rest of my life, what will really give me satisfaction? If you can help me out on this one, let me know, because right now I sure am confused.