You have a very clear train of thought, well constructed sentences too.

An interview with my boss

I had an interview with my boss the other day .
I set the goal for this half fiscal year with him.
I was recommended for a chance to get the Hazardous Materials Engineer's License class A special group .
However I don't have enough time until the exam takes place, so I have just started to study for class B group 4.
I often become sleepy while studying for the exam.
Does anybody know how to get rid of sleepiness？

And to answer your question, try sneak in at least a 15 minute nap whenever you can every day, and try look for ways to make your studying interesting so that you can stay motivated. 
I hope this helps :)

-Baraka