Being unfairly fired from your job is tough, particularly when it was for an unfair reason. Sometimes the unfair reason is also illegal and sometimes it is not.
There are no laws against firing someone for unfair reasons unless it is also an illegal reason. Examples of illegal reasons are firing someone for complaining about unfair treatment on the basis of race, religion, sex, sexual orientation, wage or safety violations. It is also illegal to fire someone because they are perceived as disabled, or because they opposed certain types of illegal workplace conduct.
On the other hand, being fired because your company wants to save money or thinks you are lazy is not illegal. These are just a few examples. If you want to find out whether you were wrongfully terminated contact a qualified employment lawyer.