Returning to the original question in the subject line, I believe that God has a major overall plan.
Where did we come from? I believe God created us for His fellowship. He made a perfect place, and originally perfect creations in man (He called both Adam and Eve "man" btw

Adam was the one who named Eve, along with the animals

) He also gave man a freewill, for He did not want robots that He had determined would serve and worship Him. He wanted His creation to worship Him for what He is, Love and Magnificence.
When man became imperfect, well we all know most of that story, don't we? So God knew what He had to do, and that was to Provide a way for man to become perfect again. We don't know nor understand the mind of God, but I believe the Bible is God's Word for us to read and study and know what He wants us to know in that respect. So I can't debate (or won't?) the WHY of God requiring a blood sacrifice, but He did/does and thus provided His Son, also God.
Where are we going? I believe the main purpose for us to be alive is to worship God. Short and sweet.
Those who find God will "live" forever with Him, once we are made into a perfect state again. Those who do not find Him will "live" out of His presence forever. That's what I believe.
I think it's very common, in fact, probably the most often queried thoughts, these of who am I and why am I here, in the entire world since the beginning of time???