How should I make it up to my parents?

Firstly, they are angry because they love you. Obviously you are in trouble and need help before it gets out of control. you need to talk to someone. You could try your mum. Sit her down and calmly explain how your feeling. She'll appreciate how you feel and your honesty. Its a start. Or a relation of your dads. It would be easier talking to someone who understands and loves and misses him too. Then repairing your relationship with your parents. That old expression actions speak louder than words. You have to earn their trust back. good luck.