I went to a very competitive public school. They looked at more than just my grades. I'm sorry that you got rejected, but quite frankly, if you didn't get good grades, it's hard for a school to vouch for you mastering basic skills you'll need at the next level. If however, those grades are a reflection of one of many problems of obstacles you may have faced, then that's where your personal statement comes in. If you decided to do your own thing, then as someone reading applications, I'd rather give your spot to someone else and wish you well in that sense.

Whether you decide to go to college or drop out is a decision I hope everyone can live with either way. At the end of the day, yes, find what you love and do what you love. Schooling is a great, great way to learn how to do many things, meet many great people, etc. It's not the only path, but it's an easier path for most people because you have the threads of people who came before you and would know how to guide you--assuming you're on the lookout.