New Word/Phrase I Learnt Today: Dziękuję bardzo!

I had so much work to do today at work that I had no time for anything!  Marzena came by to help me out and I was so grateful that she had time to help me that as she was walking back to her desk I shouted "Dziękuję!"

Later I told her I really, really appreciated her help so I asked  Jak to powiedzieć ...Thank-you very much?

To which she replied "Dziękuję bardzo".  (jen-koo-yeh bard-zo)

How Do You Say.... ARE YOU KIDDING ME?

Are you kidding me?

in YOUR language?

Is it something you say or do you say it a different way or is it an English phrase only?