In my experience many corporations tend to have stupid processes, when it comes to layoffs. They are all made for the worst case senarios when an employee goes berserk.

Nobody involved actually wants to be involved in the process.

Usually this is why they don't talk "about it".

And everybody wants it quickly over.

In your case :

- the company has proved that, WHEN they want to let you go, You will the last person to know,
- You must prepare Yourself for changing a job, cv, letter of recommendation from your current boss, looking at offers, 
- if they want You to stay, negotiate terms such that You can survive a few months without having a job from the moment they decide to let you go,
- if You decide to stay with a promotion, negotiate a period of more lenient evaluations or request trainings, education, a manager as a coach,.. Whatever You need to fulfill the role adequately.

Motivate your requirements that:

- You proved Your worth for the company
- You have not created this situation, which You feel unsafe in
- You need to feel safe, 

Whatever decisions the company makes, whichever manager changes, whatever! To feel safe You need it on all on paper.