Thank you for your follow-up, Priscilla.
Watching employees by the employer is permitted as it is considered to be management of human resources, and that is not harassment or a violation Similarly having your own boss ask you questions about your work is likewise within the scope of normal management and review, even if that did not take place in the past. To put it in perspective, if your boss asks you about your work and continues asking questions solely about your work, or offers suggestions or even criticism of how you work, that is permitted; but if he critiques you by stating that you were wrong because you were a woman, then it would violate the law and allow you recourse. The latter is just one example, I wanted to simply show the difference of permissible and impermissible behavior.
You would only have grounds if you can show that the behavior toward you is somehow not work related at all but is instead base don factors such as your age, gender, race, religion, national origin, creed, or disability if any. Then you could contact the EEOC
and file a grievance with them. If the EEOC agrees that the employer's behavior is out of line, they can issue you a 'right to sue' letter which you could then take to a private attorney, retain their services, and file suit.