Thank you for your question. Please permit me to assist you with your concerns.
To have a case for legal action you must show that either her behavior was discriminatory under state and federal employment laws
(such as based on your age, gender, race, religion, national origin, creed, or disability if any), or the employer breached some sort of a duty outside of employment which caused you injury. This, in your case, is going to be tough to show. By your own words she was not discriminatory, merely rude, demeaning, and intimidating. That, by itself, is not a violation--the boss does not have to be nice, and filing suit against someone who is a jerk is simply not good enough of a legal reason for it to be binding. If you can find potential grounds based on the factors I listed, then I could possibly re-evaluate or even amend my response, but at least so far you have not shown anything that would give rise to a successful claim.
Please understand that I am not condoning the employer's action who very likely overreacted or intentionally waited for this event so as to find an excuse. But that, by itself, is not yet actionable.