How are you Catholic?
The term "independent" does not refer to our spiritual state but a jurisdictional one. This term is used to differentiate ourselves and prevent confusion. There has long been a history of autocephalous communities within the Universal Catholic Church that have maintained valid sacraments and are, in fact, true Churches.
Speaking on this issue, then-Cardinal Josef Ratzinger wrote,
"Therefore, there exists a single Church of Christ, which subsists in the Catholic Church, governed by the Successor of Peter and by the Bishops in communion with him. The Churches which, while not existing in perfect communion with the (Roman) Catholic Church, remain united to her by means of the closest bonds, that is, by apostolic succession and a valid Eucharist, are true particular Churches. Therefore, the Church of Christ is present and operative also in these Churches..." (from Dominus Ieusus)
Additionally, we adhere to the first seven ecumenical councils, and celebrate all seven sacraments, the Nicene Creed, and the Apostles Creed.