Tired day

Today is a tired day. I have classes from 8.00am until 6.00pm, almost six hours are attending the classes. I feel sleepy because do not take a nap at the afternoon. My shoulder is painful, not because of play badminton. Maybe...I am too tired or still haven't take time to rest.  Is that every university student like that? Can I have a joyful university's life without stress?  I'm really tired.