Hey, my advice is to check out the uni and their business management program just to suppress the doubt a little.
When I started Pre-U, many made me feel little because the college I was studying in wasn't popular for their A levels program.
It took time for me to diminish my insecure feelings but when class begun, my lecturers were very involved and devoted to my academic progress. Soon after, other opinions didn't matter anymore.
So, I understand the whole inferior feeling thing but look at the bright side, a door may have closed but another opened. And that's your opportunity right there!
Just make the best of it and work hard for your future. nothing ever comes easy, anyway.
Many students don't have a chance like yours and have to retake papers, you know?
Maybe talk to your parents about how you feel? More often than not they only want the best for you.
All the best for your future endeavors!