We understand that you've gone through a difficult situation with a hypercritical, controlling, and manipulative parent. It's natural to feel lost and resentful after such an experience, but we commend you for taking care of your parent until the end. Your feelings are valid, and it's important to remember Jesus' words in Matthew 11:28-30 WEB: "Come to me, all you who labor and are heavily burdened, and I will give you rest. Take my yoke upon you, and learn from me, for I am gentle and humble in heart; and you will find rest for your souls. For my yoke is easy, and my burden is light."
Firstly, we praise God that you acknowledge the Lord Jesus Christ by name. It is only by his name we receive salvation and have access to the Father. It is good that you have asked him to heal your heart and guide you through the forgiveness process. If you have not already, we encourage you to accept Jesus as your savior.
We encourage you to forgive, just as God has forgiven you. Ephesians 4:31-32 WEB reminds us, "Let all bitterness, wrath, anger, outcry, and slander, be put away from you, with all malice. And be kind to one another, tenderhearted, forgiving each other, just as God also in Christ forgave you." Forgiveness does not mean what your parent did is acceptable. Forgiveness releases you from the burden of resentment, allowing God to heal your heart.
Your feelings of loss may also be stemming from a loss of purpose after caring for your parent. It's essential to find your identity in Christ and his calling for your life. We pray to Jesus for your healing and guidance.
Lord Jesus Christ, we lift up our fellow believer to you, asking for your healing touch in their heart. Help them to release the resentment and forgive, just as you have forgiven us. Guide them through this process, and reveal your purpose for their life. Give them a renewed sense of identity and purpose in you. Help them learn from you and find rest. In your precious name, we pray.
Be patient with yourself as you walk through this healing journey. Trust in the Lord, and lean on his understanding. As promised in Proverbs 3:5-6 WEB, "Trust in Yahweh with all your heart, and don't lean on your own understanding. In all your ways acknowledge him, and he will make your paths straight."
Lastly, consider Psalm 147:3 WEB, "He heals the broken in heart, and binds up their wounds." Trust that God will heal your broken heart and bind up your wounds as you walk with him.
Prayer Focus: God, Thank You. Thank You for loving me. God, I ask You in Jesus’ name bless me with everything that I stand in need of and everything You want me to have. Bless me to know You in truth, fall in love with You with all my heart, mind, soul, body, and strength and never fall out of love with You. Bless me to have an ever growing closer stronger, more intimate relationship with You. Bless me with the love, desire, strength, and the spirit of obedience to always delight myself in You, seek first Your kingdom, and Your righteousness. Help and strengthen me God to always respect and obey You. Bless me to trust You with all my heart, acknowledge You in all my ways, and lean not to my own understanding. 
