bus\first day of teaching

My heart is now bursting with excitement from the 3 classes that are scheduled later today. Classes in Japan are 50 minutes long with a 10 minutes break.I was confused when I saw some of my team teaching timetables with h written on them which I guess means hour. My supervisor told me I have a tough afternoon ahead as I will be teaching consecutively for the last 3 periods straight. After yesterday's debacle, I really hope I can survive? As if I have a choice?