anker, in Revelation 13:8, it reads that Christ is the Lamb slain from the foundation/creation (depending on your translation) of the world.
However, in Philippians 2, we read that Jesus humbled Himself, giving up His heavenly perogatives in order to be our Savior, via complete obedience to the Father.
Thus, since the Holy Spirit was His 'informer' of the knowledge He was to have as a human being, Jesus knew that He must be given over to be killed. Because He was completely obedient, as we cannot be, to the Father, He knew His human death was unavoidable. But I don't think that is what was causing Him anguish the night before.
In John 17:3, we read that eternal life is to know the Father and the Son whom the Father sent. Thus, logically, eternal death is to be forever separated from God.
Jesus went into death. It was that separation from the Father which would have caused far more anguish than any physical pain. The Bible says not just that He died for our sins, but that He BECAME sin for us. This required separation from His Father -- something that had not happened in all eternity past and would not ever happen again. But for us, for that moment in history, the love of God for us rather pitiful and rebellious creatures of His was shown its entirety by the fusion of the two wills within Jesus -- the will of man and the will of God -- culminating in His crucifixion and entry into death itself.
Which He then conquered. For us.
That is the terror and the glory of both the Crucifixion and the Resurrection.
The mention was made that this means either Christ cannot be God or that Christians have more than one God. Christ Himself answered this when He said that He and the Father are one and that the Holy Spirit is exactly like Him, and the Spirit of Truth. Jesus said also that HE is the Truth. We cannot understand this anymore than an unborn baby could understand if someone talked to him about chocolate pudding or beautiful sunsets. But the truth will be made understandable later. Right now we have faith that what Jesus said is true because those of of who are His know Him personally. He know He indeed IS the Truth.
And it only makes sense, really, that the reality of the Creator would not be fully understandable to any part of the creation, doesn't it? What are our minds compared to His? What is our knowledge compared to His? He is by far the greater, and it is utmost arrogance to think we can or should understand all about Him.