It doesn't sound like a lawyer would be much help to you unless you feel your employer discriminated and unfairly or illegally terminated you. In your case, unfortunately you were fired for no reason, but they gave you your entitled severance. The other consideration is lawyers cost big dollars -- $300/hr on average. Instead, this link gives you a good rundown of what's legal and what's not:
CBA British Columbia - 280
You're most likely still eligible for EI benefits, unless there is proof you were dismissed because of misconduct on your part, or you voluntarily left your position when you didn't need to.