Help leaving deli

I've been at Wawa for a little over a week now and it's mostly been deli, but I've been trained on register as well. I understand that it can take some time to get used to things. But I know my personality and how I can get very nervous and anxious with things.

I wanted to get trained other than register because I know it helps to know everything. But I have just been super uncomfortable and dreading every time I come in and have to work back there. Again, I know things could get better with time but I just don't see me becoming any less anxious back there, especially when things get busy.

I talked to my manager who seemed to understand where I was coming from, but basically said I have to be back in deli for at least a few weeks. I just feel like they shouldn't be able to force me to do something I'm clearly uncomfortable with.

Is there anything else I can do or someone else I can talk to about not having to be back in deli?

EDIT: When I say I'm anxious, it's not with everything. I am perfectly comfortable being on register and don't mind the rush up there. There's just a lot more that goes with deli and my problem is that I panic and freeze when things start going faster. Just doesn't seem fair to me, my coworkers or customers if I can't be at my best. I had two different cashiers tell me that they never have and never will work deli so obviously it can happen at this store.