So nervous about med errors

I am very early in my education, and I will be starting the prerequisite courses for nursing school next month. I have a prior bachelor degree, so I hope to be through nursing school and graduating with a BSN in roughly 3 years.

I am just so very nervous about hurting someone with a med error.

This past fall, I worked in a high school kitchen. This kitchen is somewhat unusual in that we make everything from scratch. At first, I diligently hunted for the proper measuring cups and measuring spoons, which were often hard to find or so dented that they were no longer accurate. Then I would measure everything properly with leveling off the dry foods or doing quick conversions on paper if necessary. The problem is this process takes time and with our kitchen being so chronically understaffed, there just wasn't time to do things the "right" way. After being almost late to getting food out on the line several times, one of my supervisors took me aside and showed me how to measure food by pinches and handfuls, pretty much eyeballing everything. He also told me to stop using conversion charts and just do everything by guesstimation. Well this didn't turn out very well. After I started doing things this faster way, I started making mistakes all over the place. Twice as much sugar one time when trying to convert a recipe written for quarter cups to gallons. Another time apple cider vinegar was stored in the wrong place and I used it instead of sesame seed oil, which has identical color, viscosity, and packaging.

I always caught my cooking errors shortly after the problem, but this still has me very worried. I know that using the metric system rather than English will help immensely, but is that enough?

On the other hand, I cared for two grandparents through home hospice as the primary caregiver. Each time, I administered the majority of the medications. The home hospice nurse never had any complaints about anything I did during that time. I've also cared for 2 children through all the usual minor illnesses. There is only one time that I can remember where I had a legitimate med error, and it was for myself. I accidentally gave myself too much of a cold/flu medicine because I mis-measured the med in tablespoons rather than teaspoons on the universal dosage cup.

Is there any hope for me? I don't want to hurt anyone!