Republic Act No. 10173 (Data Privacy Act of 2012)
Section 13 — Sensitive Personal Information and Privileged Information — Special Protection for Medical Information
“The processing of sensitive personal information and privileged information shall be prohibited, except in the following cases: (a) The data subject has given his or her consent, specific to the purpose prior to the processing, or in cases where the processing of the same is provided by existing laws and regulations; (b) The processing of the same is necessary to protect the life and health of the data subject or another person, and the data subject is not legally or physically able to express his or her consent prior to the processing; (c) The processing is necessary for purposes of medical treatment, is carried out by a medical practitioner or a medical treatment institution, and an adequate level of protection of personal data is ensured; or (d) The processing concerns sensitive personal information necessary for the protection of lawful rights and interests of natural or legal persons in court proceedings, or the establishment, exercise or defence of legal claims.”
Your medical condition is sensitive personal information under RA 10173. Disclosing it to a client without your consent falls within none of the permitted grounds. The employer violated Section 13. File a complaint with the National Privacy Commission at privacy.gov.ph.
Republic Act No. 10173 (Data Privacy Act of 2012)
Sections 25-31 — Penalties — Criminal and Administrative Penalties for Unauthorised Disclosure
“Any person who, without the knowledge and consent of the data subject, discloses unwarranted or false information relative to personal data shall be subject to imprisonment of one year and six months to five years and a fine of not less than five hundred thousand pesos but not more than one million pesos.”
Unauthorised disclosure of sensitive personal information carries criminal penalties. File an administrative complaint with the NPC, which can also recommend criminal prosecution to the DOJ. Document all evidence of the disclosure — emails, witness statements, and the employer's admission.