First, you need to get good guidance on how to pursue career training and/or academic courses that will place you on track with your interests. If college is a definite part of your career plans, I would also ask to speak to college admissions counselors in person or at least on the phone. Ask them what it would take to gain acceptance to their schools -- certain grades, courses, experiences, recommendations, and so on. Once you know what it takes, you can begin your "comeback," knowing that all your efforts will be in line with getting what you want.
I would also suggest not only seeing your high school guidance counselor but also a private, well-respected college/career advisor who specializes in giving advice to kids in your situation. You will need to prioritize some of your "numerous amounts of different careers" so you can be more focused in your pursuit. Just working with a professional consultant on this one issue and maybe taking some occupational/career aptitude tests will help you in your school and career plans.
There are many kids who are going to college merely because that's what is expected of them. They have no real desire to learn more but don't know of anything else to do with their lives. You, on the other hand, are full of hopes and aspirations and a desire to learn. Hold onto the hopes that you have. With the right professional help and guidance, you will get your chance. I know that you are ready to work hard to reach your goals. Keep me posted on your progress.