How do you take criticism about your work product?

Here's the low down : I'm the highest level before management. There are only two of my position in my office of 30 people. At this level I handle bigger /more difficult /more time consuming assignments.

The other person in my position had 64 cases. I have 165.

I was called in and asked why some of my numbers were not up to par. I said I'm busy, I have a larger work load than others. I was told no..(This is where I need help)... I said "bullshit"

So the numbers were pulled and I was proven to be right. But it had already deteriorated and I started the beloved frustrated crying. I excused myself, pulled it together and went back.

I was told I'm defensive and I need to take criticism better. Which I don't disagree with. But god help me... How?!?!?

How do you do it?? I do take my work personally and it frustrates the living heck out of me that management isn't aware of case loads(the numbers are printed DAILY!!!)