Supper random question just wondering what y'all would do in my position

So every morning I drop my son of to my parents house before I go to work. My parents are smokers, i am not, and every so often, not often at all actually, they will call me in the morning and ask if I can pick up a pack on my way to their house. Normally I do not mind doing this, however since being noticeably pregnant I do not feel comfortable with this at all!! I feel like gross walking into a store 8 months pregnant with a4 year old next to me buying cigarettes.... Am I wrong? Am I just to worried about what people think of me? I know they are not for me but other people don't and I just feel so uncomfortable with it. What would you do???