get over my telephone phobia

every time i have to make or accept a phone call from anyone i don’t regularly talk to on the phone, my heart pounds, my head gets light, i feel like throwing up. usually i can get myself to actually make the call, eventually, after playing and replaying in my head what i will say, and usually writing notes to myself. its really pathetic and frustrating. and now that i’m working for myself as a massage therapist, i need to actually take calls from clients to set up appointments. its hard. so far i’ve only had a few, and each one has been a small struggle to book. i dont know what the deal is. i’m a very visual person, and part of it has to do with not being able to look at the person. ... although i have this goal, i’m not sure how to overcome it.