Help me!!??

Whenever I eat out I feel sick. Sometimes I literally start gaging, but I’m worried that one time I will through up. I think the reason i feel sick is because I’m worried I won’t be able to swallow propaly and I’ll die.or I will feel sick all the way home in the car.i have I breathing technique that stops me from throwing up I also use it when somebody burps. Because I feel like those bad air will go inside me. One time I actually throw up!! What should I do. Not eat out ever again?? I’m going on holiday today!!