What to replace "the author" with

[taytotayto]

I'm doing a nursing masters and was told by my head of department that I was marked down on a recent essay as I used "the author" when talking about myself in the essay. I then asked what should I use instead and was told to be imaginative ! Honestly...... What kind of help is that. So what can I use instead, can anyone give me some advice.

I'm doing a PGCE (post compulsory) and often refer to I or my (eg class) or mine, so first person. I haven't yet been told that's not OK.

Can you refer to taytotayto (2014)?