What if you were sick but didn’t have anymore medicine? Can you go to the store and get it?

I’m sick as a dog and I can’t go anywhere because of it. I took the last of the medicine and now I’m out. I don’t think I should go because I don’t feel well and I’ll get people sick. My grandparents aren’t home right now. I tried to call but they didn’t answer. Hopefully they’ll answer soon.