I noticed, when I'm about to speak on the phone, my breath becomes unregulated

I noticed, when I'm about to speak on the phone, my breath becomes unregulated So let's say I call to my clinic to make an appointment, while the phone rings and I wait for them to answer, something happens to my breathing. I stop breathing, or I breath really unregulated, and I believe it is causing my stutter to be much worse. I noticed this today, and the funny thing is, I noticed it while I was **pretending** I'm making that phone call. So if it happens to my while I pretend, this 100% happens to me in reality as well. Anyone can relate?