Strict Parents! Help Please!?

So today I got my repost card back. I had four A's and a B+ (in math). Unfortunately for me this trimester I was sick A LOT so i missed about 11 assignments in math. My dad is freaking out, and not letting me use the computer besides for school purposes( he doesnt know im on right now) and i cant hang out with my friends this summer. School Starts in more than 2 months and I cannot deal with being alone all summer. What should i do?