I've worked call centres before and they sure are nasty environments for an introvert. I was usually glad of taking a call as it provided a distraction from the office. I used to feel more anxious between calls than during them (and I'm someone who finds using the phone anxiety inducing so that shows how awful it was).

Do you work for a big company? If so could they shift you into another job role, perhaps more admin based / in a quieter office?. You may be surprised how much they value your work if you talked it over with them and they may want to keep you in another role rather than see you leave due to stress.