When you are the suspect of a crime you have a Constitutional right to remain silent. You are never required to give evidence that can be used against you. You can simply tell the police officer that you have nothing to discuss with him until you've spoken to a lawyer. He will know what that means.
Getting the police officer angry at you isn't a good idea. And it shows you have a temper, which is not good if you're going to be facing a harassment charge. Still, typically, when the police come calling you for information like this, it usually means they don't have enough evidence to arrest you. So if you didn't tell him anything about what you did or didn't do to the complainant accusing you of harassment, this may never become a court case.
If the police reach out to you again, just tell them that you know that you don't have to agree to answer questions and you have nothing more to say about the incident they are investigating. Anything you do say about it can be used against you, but refusing to answer questions cannot be.
In the worst case scenario, the police will find the evidence they need elsewhere and you're going to face harassment charges. You don't need to retain a lawyer yet, because there's nothing for that lawyer to do, but while you've got the time you might want to get a couple of free or low-cost consultations with a criminal lawyer so that you will have one just in case one day the police turn up with a warrant for your arrest. At least you'll have the name and phone number of a lawyer who will already be up to speed on your situation and can jump right in and protect your rights.