Consider writing a letter from your heart to your parents about how they have made you feel. Don't make it a letter full of blame. Talk about how their unrealistic expectations cause you to feel lots of pressure and tension. Tell them that you don't want them to love you or be proud of you only when you live up to their expectations. It would be great if you could sit down with them together and have a calm talk about what you feel.
You have every right to be saddened and disappointed by your parents' insensitive reactions to your report card. I am sure that they think they are doing their "job" by telling you that you must work harder. Please write that letter to both of them, seek the help of your guidance counselor (and any other trusted adult family members), and continue to challenge yourself in your desire to learn and grow. Keep me updated if you'd like. I'd appreciate hearing how things are going.