How do I find out if my firing was wrongful and what to do?

Not knowing your rights is a fixable problem, and the fact that you are asking is the right first move. A firing can feel wrong and still be legal, or feel routine and actually cross a line. What matters is the reason. Losing a job for an unfair-feeling reason is not always illegal, but being fired for certain protected reasons, or in breach of a contract, can be. Start by writing down everything while it is fresh: dates, what was said, who was there, and the reason they gave you. Gather your emails, your contract, any reviews or warnings. Facts fade fast, and your case, if you have one, lives in the details. Do this before anything else. Then get one informed opinion. Many employment lawyers give a free first consultation, and your area likely has a labor board or agency that handles this at no cost. Bring your notes. You do not need to understand the whole law. You just need one honest read on whether you have something worth pursuing, and what your window to act is.