Hmmm... my dad came from a similar situation to yours. He lived with a whole family of 11 people in one room, his father often couldn't even pay for food for the children, luckily for him he did have a mom, but it was hard. You know what though? everything did end up turning out alright for him. now he lives in the US, and all of his brothers and sisters have jobs and support themselves. I am not too familiar with the job situation in indonesia. But I will say this: if your dad wants you to go to school, do go to school, and don't give up on that for a job. Do good at that, you never know what tomorrow will bring (money for food and schooling for example) Your father makes sacrifices for you so that you can have a good life. My grandfather did the same thing for his children. When you get old, and your father is old and grey, you can repay him then for all he is doing for you now.
Just to sort of tack on to puppy's comment, have you guys considered any sort of government assistance? I'm not sure what exists where you live, but often governments tend to be helpful when a child is also in that sort of situation.
Have you tried having your dad talk to your school and explain the situation? They may have some assistance for low income families.
As for the work and school conflict, do you NEED those school activities to graduate? If not, then they're just going to have to be cut. Its one of those decisions you're going to have to make for the rest of your grown up life.
If you don't want to try for a job as a waitress or in retail, you can try odd jobs for people. Walking dogs, cleaning house, yard work, etc. In the spring you might be able to find somebody who needs help with a garden who is willing to trade you greens- remember there are more ways to get food than just working for money, I trade rabbits (for meat) for physical therapy.
It's a cliché to say, but, yeah, just have faith in yourself and your abilities, and things should work out sooner or later. If you can't afford school right now, go to work, and study later if you wish. There are always options, although I do understand how situations like that can be paralyzing. It all comes down to attitude I guess: the more you believe things won't work out and everything sucks, then they definitely won't work out. Just... Believe in yourself.