First a question: what religion were you brought up in?
Contrary to many other Christians, I have never felt any troubles comprehending the Trinity. There is but one God, but he shows himself to us humans in three separate identities, the Father, the Son, and the Holy Ghost.
You can compare it to the separations of power that is the foundation to most Western governments. The Government is separated into one Legislature (Parliament/Congress), one Executive (King/Cabinet/President), and one Judiciary (Court system), but it is still one government for one country. God has separated Himself into one Creator/legislature of laws of nature (the Father), one Executive (the Holy Ghost), and one Judge (the Son, who will judge mankind after the resurection).