Nobody enjoys being fired, but the whole experience is somehow vastly worse when you know you don't deserve it and believe it's nothing more than retaliation for exercising your rights as an employee.
The important thing to do in this situation is to focus on your goals and your future -- you want to leave yourself in the best possible position in case you decide to pursue legal action based on a wrongful termination.
1. Stay calm
Losing your temper or getting emotional isn't going to help your situation -- but it could hurt it. Do your absolute best to push your emotions to the side until you get home.
2. Ask questions
Ask your employer what the justification is for your termination and pay close attention to the answer. It could provide some important clues about whether you're firing was retaliatory in nature or otherwise illegal. Other questions to ask include whether you'll be given any severance pay and how -- and when -- you'll be compensated for your unspent vacation and sick leave.
3. Take everything you're entitled to take
If you're given the opportunity to clean out your desk, make sure to take your copy of the company handbook, copies of any correspondence you've had with your superiors and letters obtained from human resources. Some of that may have an evidentiary value that can help you prove that you were wrongfully terminated.
4. Don't discuss your situation with others
Keep your situation quiet for now. There may come a time when you can feel free to discuss what happened, but right now you want to be as discreet as possible until you decide whether you are pursuing legal action. Make sure that you don't give out any information on social media either.
5. Consult an attorney
If you believe that you were fired in retaliation for exercising any of your legal rights as an employee -- such as reporting unsafe working conditions or filing a harassment complaint -- take a day or two to recover. Then, contact a wrongful termination attorney about your case so that you can learn as much as possible about your right to take legal action.