Social anxiety

I just got my first job (I'm 18) at PetSmart, I'll mainly be working with small animals but I'm going to be cross-trained with the registers and that'll be my first task. I have social anxiety and I wasn't aware I'd be put at the front, does anyone have any tips on how to control or 'get rid of' this type of anxiety? Any cashiers have any advice on what to say, how to handle things, etc? Any help is very much appreciated!