There's a rule of thumb that says it takes 1 day to adjust for 1 hour of jet lag, so yes, you ought to be back on normal time by now if I understand your time difference correctly. But it takes some effort. I prefer the violent zombie method. No matter how late you fall asleep tonight, you MUST be up by 7 tomorrow morning, and stay awake until normal bedtime. Physical activity helps. Repeat for three days. Discipline, man. Don't let Japan ruin your education.