Just started as job where I have to talk to people on the phone. I need some advice

Just started as job where I have to talk to people on the phone. I need some advice Some background information: I'm 17 and have a job at my uncles company now for the next 6 weeks. A big part of the job involves talking to people on the phone. I've known I was a stutterer since i was maybe 13 or 14 but I didn't really pay much attention to it because it wasn't that serious. However as I've gotten older it has gotten a lot worse. I've been to see a speech therapist and my stutter is definitely caused by anxiety. I'm mortified of talking to people in case I stutter, which of course I end up doing and it causes a sort of vicious cycle. I was hoping if you wonderful people could perhaps recommend some courses of action that I could take? Like for example book recommendations, or helpful videos/websites/articles :) I plan to become active around here for the next while, and hopefully I'll let you guys know how I get on :)