God knows our limitations, and He doesn't condemn us for them or hold us accountable for things we aren't able to do -- whatever the reason. And as an aside, I'm sure God was pleased with you for your willingness to help your mother during a difficult time.
At the same time, God wants us to do what we can, and not use our limitations as an excuse to ignore our responsibilities. No, perhaps you can't read very well -- but you can read, and even if you read only a few verses a day from the Bible, God can speak to you through them. You might begin by reading a few verses each day from the book of Psalms, asking God to help you understand it and apply it to your life. Let the Psalmist's prayer be yours: "Teach me your way, O Lord, and I will walk in your truth" (Psalm 86:11).
But we also learn about God's Word in other ways -- through sermons we hear, or messages from gifted Bible teachers, or even through our informal fellowship with other believers. God loves you, and He wants you to know Him and love Him more and more each day.
Make sure of your commitment to Christ; if you have never done so, ask Him to come into your life today. Then thank Him that you now belong to Him, and ask Him to make you an example of Christ's love and kindness to others.