doucumentation?

Hi. I have worked for a major rehab hospital for 15 years. Yes same company. have seen lots of people come and go and changes through the years. I am an LVN. I have never in all my years of nursing ever had a pt. complaint. I do have the DON from hell though. My hospital quit have respiratory therapist to work at night and so the breathing tx were handed off to nursing. The Rn's were doing them then we went to primary care so everyone did there own pt. We were never trained for it and we never knew for a while there was a book to write the tx down in. One of the RT's told us one day. Well making a long story a litttle shorter - I had a tx due at 2am and at that time I had one pt down the hall throwing up and two jumping up out of bed to go to the bathroom. This took the help a the one aid we had and the RN went down to the lady throwing up. After everyone was safely in bed I went an did the tx. The man was mad it was late and wanted to know where respiratory was at. I explained they were not here at night but I did bring his tx and ask was he ok or short of breath. He said no he was ok nut though his tx should be on time. I said I was sorry and gave th tx and signed it off in the book. The DON from hell called to ask why he didn't get his tx. and I told her he did. Now within a weeks time this has been blown up and I am on the verge of being fired for false doucumentation since the book said the tx was given at 2am. What can I do I appreciate any thoughts about this. Sharon