No.
Valentine's Day is the feast day of St. Valentine of Rome, a priest and martyr in the early Church.
The remains of Saint Valentine were removed from the Catacombs of Saint Valentine in Rome and placed in a basilica in Terni, Italy in 273 AD. Some relics attributed to Saint Valentine were also claimed by the Franciscan church in the Church of St. Praxedes in Rome.
St. Valentine of Rome who was a priest or bishop in the early days of the Church.
No, she is not a Doctor of the Church. She is not a saint yet.
No, St. Paul is not a Doctor of the Church.
Yes, Valentine of Rome is a Catholic saint. He was a priest, possibly a bishop, in the early church. He defied the Roman emperor and was imprisoned, tortured and martyred.
Pope Saint Leo I (the Great) was promoted to Doctor of the Church in 1754.
We celebrate Valentine's Day, because until 1969, it was one of the many Saint's Days observed by the Catholic Church. It was dedicated to the patron saint of romantic causes, St. Valentine.
Because of his schism with the Church, Tertullian is neither a saint nor a doctor of the Church.
The Catholic Church recognizes two Saint Valentines: Saint Valentine of Rome and Saint Valentine of Terni. Both are honored on February 14th, but there is some debate about whether they were the same person or two different individuals.
Doctor of the Church
Valentine died the death of a martyr - automatic sainthood in the early Church.