I don't think your parents should be angry. You wrote that you studied hard and did your very best, it just happened. Of course I don't know your parents, but if you tell them that you did all you could, I'm sure they will understand and support you.
Now, to prevent that it happens again, analyze WHY exactly it happened. Were you too nervous, didn't you have enough time or whatever? If you find the problem, think about how you can work at it. There are lots of possible solutions, so be creative. Learning methods are individual, so see what suits you. :D
And always keep in mind, university is only a small part of your life. Even if you have to leave university, life goes on and there are other things on your road ahead. (I feel weird writing this because I'm younger than you. :D)
I hope I could help and I keep my fingers crossed for you. :)

Higher-level math is really difficult to me, too. I actually dropped out of the business program because it required passing calculus. You're certainly not alone in that.

What's the problem? Feel free to send me a PM on the forums if you want. :)

find me on irc in #n-mapping or #music. Always willing to listen.

That sucks to hear, man. I go through it a fair bit myself.