I am not a doctor. Nor am I a priest or a minister. But I do know that people sometimes have a hard time forgiving themselves. That is really the first person you must forgive. If you cannot forgive yourself, take your case to God and ask for His forgiveness. Ultimately you must get beyond the pain you are inflicting on yourself by forgiving yourself. Without personal forgiveness and healing it is hard to achieve success.
Forgive Others Privately
The next person or persons you must forgive is anybody who has done harm to you. This does not mean that you tell the person you forgive them unless they are asking for it, you just need to forgive them privately, to yourself, and let it go if possible. Similarly to not forgiving yourself, not forgiving others does you more harm than you imagine. Go through the process of forgiving others. If God can forgive, why can’t you?