How would I go about winning my case?

I am a Licensed Practical Nurse of going on 2 years. Amother nurse states that I was sleeping on the job. She says her witness is the grandmother of the home I work in. The grandmother denies seeing me asleep and the other nurse works 7a-7p while I worked 7p-7a (she was not there). I deny any allegation of being sleep. She has went to Corporate with this information and I had to attend a compliance meeting. How do I go about taking this to court to state my side? She's friends with higher staff in the company and they seem to be leaning towards taking her side. I'm not sure how seeing that she has no witness and she's making this up due to personal hatred towards me. I doubt want to lose my license that i worked hard for because this lady is upset that I don't want to befriend her.