Caught in a Dilemma with Medicines

I've been working at the hospital as a nurse for five years now. Last week, we were understaffed and I was running late due to a personal emergency. In my rush, I grabbed some medicine from one of the patient's trays and took it myself instead of passing it along. The relief lasted only moments before panic set in. Why did I do this? Was it stress-induced or just careless? Now I'm questioning if there are deeper issues at play here.