Grieving is not an event.
It is a process.
Like sanctification, it will not be completed on this world.
Some Grandparents have the problem mourning for lost Grandchildren.
Grieving may be short ("an event"), may be a reasonable process of a few months to closure (considered a healthy duration), or may never end until you die (often killed by the bitterness that remains, generally from a lack of willingness to go through the grieving process). The key may very well be whether you allow Christ to take the place of the loss.
You have confessed with a repentant attitude and God therefore has completely forgiven and forgotten. At that point regarding that particular sin, should you ignorantly and mistakenly utter, "Father, forgive me," what do you do when He says, "Forgive you? for what?" which would be His response.
As I say, you do not seem to understand God's process. Clinging to past sins means you have not forgiven yourself, for which God has no compassion when He has taken care of it all.