First day of school

I arrived for classes today to start the year but due to jet lag I am dragging bigtime. I woke up this morning at 1am. I taught my first class and am about to teach the second but I don't know if I will be able to finish the whole 2 hours or if I will have to cut it a bit short. I will have to take a nap and then try to stay up later than 6pm. Another issue is that it is Ramadan so I will be woken up around 4am anyway...