Fired over OTC med I gave to patient

I have a question I work in a nursing home and one of my pts asked me for cough syrup I am a cna i told the nurse then i went to get the pt a fresh cup of ice water i came back and seen the nurse poor the cough syrup into a little cup and told her i was takin the ice water to the pt did she want me to give the cough syrup to the pt and she said yes and handed it to me i didnt think anything was wrong with giving the pt over the counter coughsyrup because the nurse said it was ok? the next day i went to work they escorted me out of the building and said i would probally lose my cna license is their anything i can do to keep them i really didnt think i did anything wrong?