Severance pay is not required by law in 47 states, including Florida, and only in limited circumstances in the other 3.
If you have a legally binding contract or CBA that guarantees you severance, the employer must honor that. If WARN applies AND you do not get the appropriate notice AND your situation does not fall under one of the many exceptions to WARN then you are due pay in lieu of notice. Otherwise it is entirely up to the employer whether to pay severance or not and if so, how much.