At a very upsetting and stressful moment, it is a good idea to cool down and write down a list of things you want to do on a piece of paper before taking any action.
Ask yourself, if they offer your job back, do you enjoy/love doing that job ?
If the answer is yes, then go for it.
If the answer is no, then you should consider only negotiate to get your termination status correct instead of a long/expensive legal battle.
Get your termination status correct ("WFR" or "no fault termination" are critical for future job search/reference) is important.