When I read 2 Timothy 2:3, I see a near perfect description of the person I've become. I cause so much pain to myself and to others. I have become a cold, blasphemous, apathetic, hateful, callous person. Please pray for me.

No matter if we pray for you, you have to go and ask God to forgive you of your sins first. Then allow him to guide your steps form now on. Open your bible, buy one if you don't have any and read it. Start with the Psalms so you can start having a personal relationship with God yourself. Read also the book of Wisdom, which is Proverbs to gain wisdom in the Lords help. Once you ask for forgiveness the past is the past and God will never hold it against you anymore. Ask Him to help you forgive yourself so you can worship Him without any hindrances in your life.
Lord help this person to come to forgiveness, and wash them in the blood of the Lamb, make them cleaner than they ever were in their life. Help them to grow in You Lord, and to be able to forgive them self too. Put a new son in their life, a song of love and praises toward You Lord. In Your precious Name Jesus I pray amen.