[Jess~]

I had this exact same problem a year ago. It was so bad that, even if I answered a sales call, when I hung up I'd be shaking horribly and my skin would kinda go cold. So yeah, I had a problem.
But I realized that the best way to get over it, for me, was to just answer the phone. Like, as soon as you get a call, just hurry and answer it, no questions asked. If you force yourself to answer it in a split second after it rings, you won't have time to think about it, therefore there'll be no time to panic because you'll already be on the phone.
As for calling people...I say, just do it still. If it's too much, try breathing deeply before the call.