I've got a low self-esteem and no confidence?

First of all let me say I'm sorry all this is happening to you. Your life sounds pretty difficult right now and that really sucks. Don't worry about your mum, live your life how you want separate from her and maybe she'll follow your example. Being happy is hard and you have to work at it everyday all day in order for it to work. Just take it in baby steps and gradually you'll be able to dig yourself out of the hole you're in and become more grounded. Try seeing a therapist, even if you can't afford there are tons of options available to you (counselor at school perhaps...). It's always darkest before the dawn... I know it's cliche but it's true. Good Luck, I care about you and I hope everything works out for you