Social media policy investigation?

[matty craig]

So I'am receiving a disciplinary investigation for breaking my companies guidelines on social media policy, basically I can't bad mouth them on social media such as Facebook, Twitter etc
I recently posted a Facebook status about "wondering what job satisfaction is" and someone from work saw this, told my head manager and now I am receiving an investigation.
Basically my argument is as follows:
I did not mention my employer at all nor does it mention my employer anywhere on my profile.
I could've easily been talking about a part time job I do on the side, a job I did for a relative etc, there's no proof that it's about my company.

So my questions are, with the above information, do you think the investigation will go in my favour and also do I have a right to know who told my head manager. Any help/opinions would be appreciated