Sin and Forgiveness

For many years I led a very unChristian life. Even after "becoming" a Christian I continued to do what I wanted and sacrificed nothing.
For the last two years I have tried harder to live a life like Christ. To sacrifice more and sin less. I had put the past behind me and moved on.

This weekend the past came out with a fury. I was reminded of the life I once lived and all the guilt and pain that came with it came flooding back. A friend tried to encourage me and remind me that those experiences made me who I am today and to regret nothing. I take no solice in that statement.
I only have one major regret in life, something I wish I hadn't done, and yes the past has brought me to where I am today, which doesn't totally suck. But the past has also left me messed up and broken, wondering who could ever love and accept me.
In church today we discussed that everyone pays for sin but no one has gone to far from the love of God. God is perfect and flawless and forgives all my failures and loves me and accepts me, sin and all.
Humans are not as loving and forgiving. Humans while created in God's image, are not God and can not always look past the faults and failures of the human form.
What are we supposed to do with that? How does one deal with their own forgiveness from God, with the knowledge that their human partner may not forgive? How does one find a human partner in all that mess?