Wait, you're grounded? I thought you just meant she won't cook for you until you finish working, not that you're not allowed to eat at all. Usually I would say respect your parents, but in this case that could cause some serious health issues. Get some food before you have to go to the hospital
Personally I think he's overreacting, I've gone two days without food before, aside from the emptiness it really isn't that bad.
What
Like I said, unless you're chugging water and being very inactive, as in, not moving, this could cause health issues. Not eating for two days isn't something you can just brush off like it's nothing