Shame: Who I am is not okay.
Guilt: What I do is not okay.
Growing up Catholic, I developed a misunderstanding of shame. The Catholic Church often gets blamed for this, and it is certainly not the only place one learns shame and shame is NOT central to Catholic teachings.
Guilt is. This is true of ALL Christian religions. (This is why the savior Jesus Christ is paramount to our salvation, but I'll save this exploration for the theologians and my private study on living the faith.)
Today, Ash Wednesday, we enter a dark period of reflecting on our guilt over our shortcomings, our human, inane falling short. Our "sin." My understanding of sin derives from its Hebrew root "to miss the mark." So as we all miss the mark, one must acknowledge guilt, ask for forgiveness -- from ourselves, from those we have wronged, and perhaps from a deity, a savior.
While it is easy to get suck in guilt, it is more important to seek forgiveness. For acknowledging wronging doing and making reconciliation is an active path. It moves toward peace.