You must have seen it comeing...Cant really blame the test/teacher unless the whole class is failing....Best to tighten up..tell the truth to your parents, ask them to help, if they can, with tutoring if your truly going to make an effort.
If you really fear abuse from your parents ( possible, IDK ) tell the Councelor.
Other wise, you should be grounded.....do everyones chores, no dateing, no video games, no car, no tv, no computer, no phone, no Ipod, no music, no food, no water, no sleep, sent to the CIA to be tortured....haha.