When you first complained of harassment, your employer should have made clear to you that it will protect the confidentiality of harassment allegations to the extent possible. An employer cannot be expected to guarantee complete confidentiality, since it may be impossible to conduct an effective investigation without revealing certain information to the alleged harasser and potential witnesses. However, information about your allegation and any record of your complaint should only be shared where it is necessary to the investigation.
There may be a conflict between your desire for confidentiality and your employer's legal duty to investigate, if you inform a supervisor about alleged harassment, but ask him or her to keep the matter confidential and take no action. If the supervisor does nothing, it could subject the employer to a future lawsuit. While it may seem reasonable to let you determine whether or not to pursue a complaint, the employer still has a duty to prevent and correct harassment.
One mechanism to help avoid such conflicts is for an employer to set up an informational phone line for employees to discuss questions or concerns about harassment anonymously. It may be too late for you, but it could prevent others from having a similar experience to yours.
If the harasser or other coworkers are treating you differently because you made a complaint, that can be a form of retaliation, which is also illegal. (See the next question for more information on this topic.) You may also want to consult with an attorney at this point to determine whether you have a legal claim based on what has happened.