How to get rid of the echo coming from your headphones while you are recording in Premiere Pro.

Hello,

I am still new, learning Premiere Pro. I have this one question that happened when I first used it two weeks ago. This never happened in Audition. But when I hit the record button on Premiere Pro, I heard my voice echo through the headphones, and the software picked it up and recorded it. This time around, I hid my headphones (While still plugged into the mixer I have), when I was recording my audio podcast. How do I make sure that Premiere Pro doesn't pick up the echo sound coming from my headphones?