The very similar thing happened to me 3 years ago. Are you in the US or UK? If you are in the UK, then probably my experience can be of some help to you. What I suggest you to do now first is to look for information over the internet on Unfair Dismissal. Judging from what you said, you were summarily dismissed, and your formal employer did not comply with the dismissal procedure required by the Employment Law. At the same time, you should write to you former employer, requesting a written statement from them on what ground(s) they summarily dismissed you. You are legally entitled to ask for such a written statement from your former employer. You should also launch an appeal to your former empolyer, asking for a review of the dismissal decision. Keep a record of all the correspondences. You should also start to look for a new job now, and also keep a record of all your job applications.
If you decide to go to the court with them, in the UK, you do not have to have a lawyer/solicitor. I represented myself and won a compensation 5 times what was offered in the severance agreement.
