All perfect praise be to Allah, The Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
What you said and did is not Kufr or even close to Kufr, and is not sinful in the first place. You are not obliged to follow this story or read it. In fact, feeling that your action is Kufr indicates that you suffer from Waswasah (obsessive whisperings), so beware of Waswasah and do not get carried away with it, especially in this branch of the religion (doubts regarding Kufr). Getting carried away with Waswasah inevitably leads to great evil.
Allah knows best.