Ask God the Father to extend his merciful and loving hand to you, accepting you back into the flock.
When we have sinned, it is tempting to think that God no longer loves us and somehow despises us.
Yet that idea is farthest from the truth.
God is in fact the Most Loving Father, and is the perfect version of the father in the Parable of the Prodigal Son. He is always there, with open arms, ready to accept us back into the flock.
Here is a prayer from The Catholic prayer book and manual of meditations, asking God for the grace to return to his loving embrace.
O most tender and most loving of all Fathers!
You are willing to receive this prodigal child,
to change my affliction into joy, and misery into happiness.
Who can sufficiently admire such an excess of goodness!
I detest from my soul my past disorders.
I am heartily sorry for them, and beg your merciful forgiveness.
I shall endeavor by my love, respect, and submission,
to atone for my ingratitude and rebellion.
Sincerely do I desire to return to you my Father:
all my thoughts, affections, desires, and actions,
shall serve this day as so many steps towards my return to you.