The problem begins with me oversharing on social media, so I realize it might be stupid to look for guidance on social media, but I haven't found much useful feedback in real life. I don't use my name, the name of any of my employers, or my exact location on this site, and I don't believe I know any of you in person. Just the same, if you think you know me, please know that I'm trying to figure out how to improve matters, not make them worse.

TLDR: I messed up my Fb privacy settings, posted something to my entire friends list that was critical of management, someone screenshotted it and sent it to HR, HR shared it with the entire senior management.

The long version:
I'm active in the union at one of my workplaces and I've been working on bargaining an issue that's been dragging on since January.

There was a recent meeting that was particularly acrimonious. It is a long reach to imagine that management was truly bargaining in good faith toward a resolution.

I posted a whiny brain dump about the meeting and some scathing opinions about the people on management's bargaining group to Facebook. It was meant to be on a custom privacy setting for whining about work that includes a few close friends, some folks who are on our side of the bargaining process.

I screwed up; I posted it to my whole friends list. I am not Facebook friends with any current coworkers, but I am friends with a few former coworkers and some people who work for competitor agencies.

I didn't realize until the next day when a former coworker (someone who had been in management in another department) messaged me chiding me for posting such critical things publicly. I had a mini panic attack that I might have actually posted publicly, was relieved but still mortified that I posted to my whole friends list. I made the post private. I messaged back with thanks for alerting me, and saying that while it wasn't public, it was shared with more people than intended or appropriate, I had fixed it, I really appreciated the message.

A few days later, HR emailed me with a screenshot of the post and remonstration that this was not helpful to the bargaining process. Based on the time zone difference of the timestamps in the screenshot...it was the same former colleague who reached out to me who sent the screenshot to HR. I don't know anyone else in that time zone.

I responded with an apology (cc'd to the union office) for my words and actions, a brief explanation that the post was shared as broadly as it was by accident, that it had been taken down as soon as I was aware, regret that my error might have a negative impact on bargaining.

Another few days later, there was another email from HR to the union office that cc'd me and the entirety of senior management. They requested I step down from the bargaining process due to my post.

The union office responded that it wasn't appropriate to make this more and more public and that management does not have the authority to remove me from bargaining.

Apparently, HR shared the screenhot with everyone that I said anything critical about and everyone else in a management role.

So, obviously, I need to apologize to everyone who has seen my post. And I need to let everyone that the current bargaining affects know what's going on so they can make an informed decision about whether someone else ought to take over the remainder of the bargaining.

But then what?

I realize I made a huge mistake.

But, I'm really hung up on feeling angry that someone who I counted as a friend sent my post to HR despite my response to their message. I also can't see why HR then shared it with so many people...that seems like intentional undermining of our personal and bargaining relationships. But also like I don't get to be angry since my carelessness got me in this mess to begin with.

Any advice? Or any commiseration from someone who's been in a similarly painful situation?