Medication errors by new grad

I started a new job recently. Unfortunately its a nursing and rehabilitation center. The patient load is horrific of up to 30 patients max! I am in a 6 week orientation program. My 3rd week of orientation I hit the floor and the nurses immediately wanted to push their boundaries. I was suppose to be getting trained on all 3 wings before being left alone; technically thats their rules and as a new orientee, you make only 23 dollars an hour to train until your 6 weeks is up. '

Last Thursday the facility was short. I had been on a certain wing for only 2 days. I wasn't familiar with the medications or the patients. The unit manager assigned me to the wing all by myself to their convience to manage 18 patients by myself. I didn't complain, I did the job because I thought I had to,even though i had no preceptor.

I gave a pain patch at 9am that was scheduled for 9pm by accident and on top of that, it was 15 mcg instead of 50mcg. I am not making any excuses for my mistake, it was an honest mistake. i am working out of a MAR that is scribbled upon day in and day out..its unorganized, messy and it shouldn't be allowed to be used. All medication administration records should be electronic. The 9pm looked like 9am and the dosage I just totally missed. I guess this is what will make me a knowledgeable nurse.. learning from my mistakes.

The ironic part is although i admitted to my mistakes, the unit manager claims she doesn;t remember me working alone as the primary nurse... i told her she is the one who assigned it and she played a part in the error... and until my training is over as a new grad.. i refuse to work alone because that error could have been avoided. Am I wrong... I felt bad.