So... This happened

I re-joined my previous company about 2 months ago in a new role. As a content writer. Both the old and new employees liked me because I have a general open and friendly demeanor.
Today my boss told me to also take up some HR responsibilities. Like conduct the first round of telephonic interviews for prospective employees so that she can only handle the shortlisted candidates.
I said okay because it seemed fun. And a back end work like content writing van get boring.
Now... My fellow employees seem a little guarded around me.
And... That sucks.