You need a work/job journal.
A work journal is your own personal record of events, statements, and concerns in your workplace.
A work journal at its best will be used proactively. Used to document the workplace generally and your work experience daily.
But why would I want to do that?
Well, I’m glad you asked! First of all, a work journal in the hands of a worker is protection for yourself, your family, and your coworkers.
When the boss can buy a BMW the same week they decide to illegally destroy your family’s financial stability, it is well worth the work to maintain documentation.
Establishing the baseline behavior of management and their treatment of workers from early in your employment will make proving retaliation, discrimination, unfair labor practices, and other boss crimes much easier.
A work journal won’t stop your boss from breaking the law but it can be a primary tool for seeking justice.
https://archive.iww.org/PDF/Organize/JobJournal.pdf
Always remember though, direct action is our sword and the law is our shield.
A work journal is not meant to make us complacent to the idea of being on the defense – shielding ourselves from bosses. It’s a tool among the many that workers can and should use to even the playing field between boss and worker.