It is possible to be successful without a degree. An education of some kind (whether college/trade/etc) can be a huge advantage in becoming successful however. I went to college for almost two full semesters after high school before facing a very similar thought process: feeling I was wasting my time and unsure if what I was going to school for would be anything I wanted to do. My decision at the time was to stop going to school and come back when I better understood what I wanted to have for a career. Shortly after that I joined the Navy to get some life experience (and a better job than what I had). That was, for me, one of the best decisions of my life. The Navy gave me a great education with a solid career path available outside the military (I was in nuclear power in the Navy, results are not necessarily typical). After 12 years I moved to the private sector and, without a degree yet, make a very comfortable living in a good job that I enjoy most of the time. I am currently in school and currently plan to start working on my MBA in 2014 as I see the advantage of both having a degree and, in many cases, having an MBA to assist with career progression in the future.
Keep in mind, however, that "success" is more than just making a lot of money. Many would argue that a person making $40k/year in a job they love with a family they can comfortably support financially is more successful than the person making $400k/year in a job they don't care for while working too many hours to have a family. What others think, however, is not what is important. The important thing is for you to balance what you want in your personal life to make you happy with what you would like in your professional life to make you happy. If you can make both things happen simultaneously that would be ideal, but most people find they must make compromises in one or both areas to accommodate what is actually available to them in life.