1. Put Your Situation In Perspective. Realize that the worst thing in this process has already happened to you - you have been terminated. The employer can't really take away anything more from you than they already have - your job and your income.
2. Keep in mind that your case is a civil case (as opposed to criminal). Neither you nor your former managers will go to jail and your case will generally revolve around whether or not it can be settled or whether it will go to trial or arbitration. Some cases are dismissed by court on an employer's motion to dismiss, and that's a natural risk of employment litigation, but that's generally the biggest risk in the process.
3. Work with the right lawyer. Work with a lawyer who you are comfortable with, i.e. somehow who strikes you as knowledgeable, personable, responsive, and who you can ask to explain not only what your course of action in your case will be but also why. Often that would not be the same lawyer who has the nicest website and who is too sure of himself. Share with your lawyer your biggest concerns so that he can address them and help you make the right decision as to whether to pursue a case and if so - how to go about doing that.