Well my father used to steal from her, and my grandfather, and from other people. Now he is prison. I am only 13 years old, and my mum unconsciously gave me his responsibilities (paying bills going shopping) hence she gave me her bank details. So it started with small things. Buying with her card, and then I started stealing larger amounts of money from her bank account, and started lying about it. Now I lie to her, and all of my best friends without thinking about it. And now I feel so bad about it.

Help

U have a best example in your life and that is your father.
If you follow him finally you will be landing as a prisoner.
So better keep that in mind first.
First talk to your mom and explain her under what circumstances you did all those.
Try to convince her first and keep in your mind that you will be a prisoner if you continue all these.
And this is not an addiction. Since you wer not caught you think you won't be caught and you are lying ,stealing. Think about the situation you have to face if you were caught. Since you are too young try to stop all these for 1 month later you won't feel like doing all this. While going out take someone with you so that you won't try to do this in front of others.

Your lack of honesty, maybe a learned behavior, can best be overcome by acknowledging the truth to your mom, and others, and admitting your mistakes.