Guilt and shame feel similar from the inside and do opposite work. Guilt says a thing you did was bad. Shame says you are. One points at an action, which can be repaired; the other points at a person, and offers nothing whatsoever to do.
That is why shame tends to make people worse rather than better. Nobody has ever hidden their way to improvement.
The way out is usually smaller than expected. Telling one person the thing you assumed was unspeakable, and watching them not flinch, does more than a decade of private reckoning.