There is God the Father, His Word, and His Holy Spirit.
Jesus being the “only begotten of the Father” seems to refer to his incarnation (see John 1:14), and here are a few of the many clear proofs of His position:
“…before Abraham was, I Am;
and: “In the beginning was the Word, and The Word was with God, and the Word was God, He was with God in the beginning;
and: “…unto the Son He saith: Thy throne, O God, is forever and forever, a scepter of Righteousness is the scepter of thy Kingdom…”
(from John 8:58B; John 1:1-2; Hebrews 1:8); but certainly, Jesus is God:
7 For there are three that bear witness in heaven: the Father, the Word, and the Holy Spirit; and these three are one.
– 1 John 5:7