Civil OP's are granted liberally in Illinois; judge's like to err on the side of caution. The question will be, was it granted? If it was, I would argue that your odds of being able to do anything civil related will be next to zero.
If she was able to get an emergency order of protection against you, the Judge would have issued another court date at which time she can ask to have it extended to a two-year order. Your copy of the emergency order will show that court date. You could show and present your evidence that the alleged abuse never happened. If you don't show and she does, it will appear as if you don't care so the order will be granted. This could affect your contact with your son as he is likely to be a protected party.
Forget about trying to sue her and move on with your life. What goes around comes around. Even if you had a basis for a lawsuit, and I'm not saying you do or you don't, you would have to show in what way, other than really pissing you off, that her false allegations have harmed you. Did you get fired from a job as a result? Dishonorably discharged from the military? Undergo extensive psychotherapy and begin a course of anti-depressants?