No kidding

After answering 4, 5 calls at night/early morning, you still go to work at regular hours?! You may get yourself killed in a car accident. Tell your boss seriously, you were busy all the night, document every single call or ticket you worked on, you have to catch some sleep or work at home in the next day. It's too dangerous for you to drive to the office. In my previous work place, a colleague got killed. If he can not understand it, you could make a complain to HR.