AIO for thinking my sister is inconsiderate?

I am home for the holidays and caught whatever sickness is going around. Body aches, headache, and cough along with chills. I've been sick all day and asked my sister if she could go to the store for me to get 1 or 2 things. We're in the northeast and it's understandably cold at the moment. The drive would take 5 - 7 minutes max each way, maybe a 25 - 30 minute trip all together. She responded by saying, "oh it's cold and i don't want to". She has no where to go tonight, I asked around 7pm, she has her own car and I said I'd pay her back. I understand everyone has free will and she's not obligated to do what i say,, but something about not helping me out just really frustrated me, especiallyconsideringshe knows I'm sick. I doordashed the stuff instead and am more pissed because I had to spend more money just to get the stuff. Is my frustration justified or am I overreacting?