Before I got married I used to live with my stepmother. Sadly the situation was bad, probably it was the same way you are describing it. (But please know that not all cases are bad, I know of many families whom stepmothers are godly women and their presence in those families have made a good, strong and powerful impact) I understand exactly how you feel, I'm almost sure I've one through what your going through by reading your words. My prayers were almost alike. One day a good friend gave me a scripture to read without me even telling her what was going on. The moment I began to read it I fell on my knees and prayer. My heart was broken before God. I can assure you that from that second my life changed, my eyes, my thoughts everything of me dramatically changed by the power if the Holy Spirit. Here is the scripture:

This is how the Lord responds: %u201CIf you return to me, I will restore you so you can continue to serve me. If you speak good words rather than worthless ones, you will be my spokesman. You must influence them; do not let them influence you! They will fight against you like an attacking army, but I will make you as secure as a fortified wall of bronze. They will not conquer you, for I am with you to protect and rescue you. I, the Lord, have spoken! Yes, I will certainly keep you safe from these wicked men. I will rescue you from their cruel hands.%u201D (Jeremiah 15:19-21 NLT)

During my prayer God ministered me with this scripture. I couldn't continue feeling defeated, I had the mighty one by my side! I had the Holy Spirit in me giving me the power to influence my family in a different way that they were influencing me. Guess what? Things began to change! It took a while and long prayers every night, but they changed! First I changed, then everything else around me. I encourage you to stand up in faith, I'm not telling you to be aggressive, no! I'm telling you to have faith, dont wait until you hear a heavenly voice telling you "this is what's good from this bad situation" no, that voice may never come. Instead pray for discernment and the Holy Spirit will surly make you see the unseen...then you will smile, everyday and all day long you will smile! She won't understand your suddent change. When you great her with joy, she will great you back not understanding what's going on. Her mouth will be shut because your joy will speak louder that no word against it would be heard. God will guide each day on what your supposed to do. Sometimes it will be nothing, to do nothing just pray and feel the peace and joy, He will do the rest.