I was on LOA and stopped into the office to drop off paperwork. Each time I was continuously harassed about my condition. (IE, dr appts, medicines, other forms of treatments, when was I returning to work) Is this not a violation of my HIPAA rights?

No. It's not.

You are not the health care provider, so HIPAA doesn't apply to what information you are asked to disclose.

No HIPAA was not violated. Your employer is just trying to figure out when you will be back as they can't hold your job forever without some kind of time frame on your part.