Congrats on the new job! The fact that you even accepted a job that would put you out of your comfort zone is the biggest obstacle to conquer and you did that. With time as you get into a routine and feel more comfortable you will just look at speaking on the phone as a job that needs to get done and worrying about speaking will just be an afterthought. In my experience at work I have been forced to interact with more people which really helps my confidence when speaking and makes me less anxious/nervous for the next time. I hope this helps and good luck! You have our support!