I can't believe I'm reading this because I'm in the exact same position!!! I'm 23, engaged (getting married June 2015), he already makes great money, and I already have one bachelor's degree and am in school for another one. However, I've realized in the two semesters since I started this new degree that it isn't what I thought it'd be and my heart just isn't in it. So naturally, I could not care less about school right now. I rarely go to class and don't do as well as I did in my first degree. The problem for me is that there aren't any jobs in my field in my area (heck- there are barely any jobs in my area PERIOD). So between the stress of trying to figure out what to do, planning my wedding, and looking into buying a house, my anxiety is really awful right now. I'm currently reading a book called "How to Stop Worying & Start Living" by Dale Carnegie and one of his first tips is to live day by day, one at a time. It's hard for girls like us because we have to have everything planned out and want to control our futures, but it's best to just focus on today. When you do that and do your best at what you're doing TODAY, you won't have to worry about the future because everything will fall into place.
Do what's best for you. Making yourself happy and being selfish are two very different things so don't get them confused-- but I think you should follow your heart and find something you're passionate about. Believe me- I know how hard that can be. I don't even know what I'm passionate about either. But resist the urge to figure it all out now. We have our whole lives ahead of us to figure it out, so just do your best every day and it'll all fall into place! If you want to talk more or need any more advice, feel free to message me :)