Lol Peacemaker I read your post as if it was a letter I had written to myself nearly 10 years ago. We seem to have shared similar concerns and dealing with an insecurity on academic success. Worse for me is I am too hard on myself, very self-critical but also competitive. My goal is to perform better than than my peers, but knowing I was going to university and be around others that were much more smarter than I was gave me some lack of confidence.
Couple things, are you currently employed? If not, try staying like that. I found that working only weekends greatly benefited my academic success, although I didn't graduate. I had a lot more time to talk to professors, study and turn in papers I was proud of. Honestly college was a breath of fresh air for me because I wasn't so consumed with constantly writing for the honors and AP classes I had taken in high school (terrible mistake to take those classes anyway), then trying to juggle some extracurriculars.
I don't know how people can work a fulltime job (or more) and still be a fulltime student. That's more self-discipline than I will ever have, but I still think the quality of your studying (and education) takes a backseat IMO. I'm probably wrong on this point, but if you can go to school and not work I think that is the most advantageous.
The best way to feel more confident is to work really hard at getting good grades. When I started getting good marks with some of the papers I was turning in, I developed more confidence, felt good about myself, its encouraging.
Math is far from my strongsuit, and at my age I'd probably have to take a remedial math course. I think I'd be much more interested now in learning than I did when I was in public school.
Like I said, I found high school more challenging and rigorous than the courses I took in college. I'm not sure if that is due to the kind of classes I took (which were more specialized), maturity, my interest, the type of proffesors, or all of it. I didn't feel I needed to spend that much time studying, but I was fortunate enough to not squeeze in studying when I didn't feel like it (unlike those that juggle a full-time job, kids, etc.). I guess it is "easier" in some respects. Maybe you can get more involved with getting enmeshed with other students with clubs, or what have you. That's the only thing I regret is not being more involved with others, meeting new people, etc. I usually just went to classes then went back home, eventhough I was very happy at the time, I could have gotten more out of my time in college.
Best of luck.