Pastel, I have a theory about my first break at 13 being caused switching from a catholic to public school around age 12. I was brought up in that system and way of thinking, and when I met people of different beliefs, I became more curious. I began to steal and behave differently than I knew. In the past, I have thought maybe it was God's way of punishing me, but no.. There's more to it.
My brother never attended a catholic school and he never developed any mental illness. It is actually a pattern I see around my area, where kids switching from private schools usually rebelling, developing addictions and mental health problems. Sometimes, I do wonder what would of happened if I never left private school.

I can't claim to be of any religion right now, but I do have faith, and believe in a creator.

Whether you believe in a God or not, it helps many people live a longer and happier life, and I have seen this first hand. I think it is important to believe in something.
What matters is what's in your heart.

I don't know what to say about dealing with your mother, but maybe giving her plenty of information on mental illness.