Extremely shy

I have had anxiety for as long as I can remember. I am extremly shy. My anxiety comes on the strongest when I have to talk to people. Mostly strangers, but even with people I have known for a while I have difficuly talking to. I have been in a relationship for almost 3 years and I still can't talk on the phone in front of him.
I have a job in a call centre where I have to talk to customers on the phone every day all day, alot of them get angry and yell at me, after this I can feel myself shaking. Before I'm due to go on the phone I go to the toilets to calm myself down and try to 'sike' myself up. I had to ask for a headset with 2 earphones so I could block out the people around me, otherwise I'd be thinking they're listening to me and I would shut down. I've tryed using a breathing tech that my sister told me about but that only works for a few minutes. The first day I was to start on the phone I faked being sick to get out of it.
Besides my parnter I have no friends. I see other people talk to people they just meet and make friends easily. My partner can meet someone for the first time and within a few minutes have a new friend.
I watch them and wish I could be like that. I wish I could make friends. I wish I could talk to people easily.
I have been to a doctor about it but he just laughed at me. I don't know what to do, I just know I don't want to be like this forever.