You can ask your parents to have you tested for ADD/ADHD, and then you'll know.
I don't think homeschooling is right for you. I think you need more experienced help than you can get at home. Does your school district have an alternative high school that you can attend, or special programs within a regular high school that can help you? I feel you need help not necessarily with the material being taught, but you actually need help to learn *how* to study. How to read the material. How to get organized. And these things are learned! You can be taught these things, if you're willing to try. But you can't do it on your own, or while you're homeschooled. You need to call in the pros. You need a real tutor.
Do your parents have any money? You may benefit from a private tutoring center, or some other sort of help.
If you can figure out what the core issues are - ADD/ADHD or a lack of study skills or both - you can get help, and address those issues. If you address those issues, you can then bring your grades up. If you can bring your grades up, you can go to college.
But if you don't get help, you're lost. So ask for the help you need. Start with your parents, your doctors, and your old guidance counsellor at your old school.