Forgiveness of one who has hurt you can be very difficult. It is not something that you can simply accomplish overnight. It takes much grace and surrender to God. And it takes prayer.
Suggested Prayer: A Chaplet for the Mercy to Forgive Others (excerpt)
First pray the Our Father. Next pray “Lord, do not hold this sin against (name) for You are full of mercy and compassion for all. Please give me the grace to forgive (name) so as to imitate Your perfect love.” Conclude with “Lord, Jesus, Son of the Living God, have mercy on me a sinner.” Amen.
Pray this often for each person you struggle to forgive. You can find the complete Chaplet at mycatholic.life website. Remember that all things are possible with God.