Don't be silly, of course you're not the biggest flop in history. Lots of students have to go a different route to get into uni because of grades. At least you got in, look at it that way, it's an achievement. Why feel ashamed of yourself? They're just letters on a piece of paper which you may be able to retake and it's still a university you got into. Also, you got an A, a top grade, and a C and a D are still passes. Who cares if your friends haven't heard of it? Doesn't mean it's bad. If you want to do the course you got in for, do it. If you don't, look at other courses, see if you can re-take or maybe get a job.
If you feel like committing suicide over your results then you should seriously see a doctor.