We get this one a lot - "is it illegal to fire me?" Short answer: probably not. Unless you have an employment contract, you are an employee at will. This means that your employer can fire you at any time for any reason. It is perfectly legal for your employer to fire you even though you are doing a great job and even if it would be silly to fire you. Similarly, you are free to quit your job at any time for any reason. Thus, most of the time, the firing is perfectly legal. Sometimes, though, it is illegal to terminate an employee. People often call this “unlawful” or “wrongful” termination. The most common examples of unlawful termination are discrimination and retaliation. It is illegal for your employer to terminate your employment because of your “protected status” (this includes things like, race, gender, national origin, sexual orientation, disability, age, etc.). Similarly, it is illegal for your employer to retaliate against you for engaging in protected activity like complaining about discrimination or improper payment of wages.
The bottom line is that while it is perfectly legal for your employer to fire you because of money issues, workplace politics, or other reasons, it is not legal for your employer to fire you because of your protected status or because you have complained about illegality in the workplace.
If you are concerned, take a moment and call an employment lawyer. Most offer free consultations.