California employees who "whistleblow" essentially call out their employers for practices that go against the law or are unethical in some way. While something like this should be applauded, it unfortunately can be met with retribution or actions against you that can make your time at work miserable and difficult.
The United States Department of Labor states that whistleblowers can face many dire repercussions just for doing their job as an employee and reporting things they see in their office that are illegal. This most commonly manifests in a sudden stunt in progress. For example, you might find yourself getting passed over for promotions despite being the most qualified. Your requests for time off could be denied. You might end up losing bonuses or taking pay cuts.
Sometimes, the retaliation can be more obvious. For example, you could be demoted. In some cases, you might be fired entirely, though this is less common. You could find yourself being the butt of rude office jokes, or intentionally left out of meetings or planning in the future. These exclusionary tactics could be a way of preventing you from continuing to report, or it could be a method of shaming or punishing you for reporting what you had seen.
Generally speaking, it can be difficult to prove that you've been negatively impacted by your whistleblowing in some cases. However, if you feel like you are being treated poorly and it started after you blew the whistle, you might want to seek a legal professional's opinion regarding what to do next.