Losing my temper

Not once but twice this happend on me. I am repeat one last time. "I AM NOT DOING PURCHASE ORDER!!"

Today or just so happen on last few minutes, again my manager ask me about Purchase Order (PO). I don't know why he didn't call admin in main office instead of ask me to call admin! Both of us are sitting in same office, how on earth i know what happen in main office? When i helping him call the dump admin, he is yelling behind me and nag on the process bla bla bla. I can't take it anymore. Everytime i call out, sure he will shout right behind me. Can't just keep quiet for a few minutes? Is this hard?

He just pissing me off!