I desperately need help explaining ASAP

I currently work at Kroger's as a Deli Clerk, and have been trying to explain to my parent's in a way they can understand for weeks now, why I can't keep working there as it is mental torture for me. They want me to wait until I get another job but I can't explain to them what it does to me to be around so many happy and normal people.
Christmas eve service is hell for me and the only way I can make it through it is to look at my phone and nothing else, last year I came within seconds of walking in front of a speeding car, this year I was unable to keep it together at my cousin's wedding and just went and sat in a corner by myself while cried inside.
I need a way to explain what I feel and how it is unbearable to my parents or I am not going to last until the end of this year.