How to help my depression?

I'm very young, only 15 years old but I've experienced alot more beyond my years. Depression is extremely common on my moms side of the family and I know its hereditary. I haven't always been the happiest person. I find myself thinking alot when I'm alone and I've been having alot of issues with my father and I. He doesn't treat me right and hasn't always been in my life. We CONSTANTLY clash and my mother refuses to accept it. She brushes it aside as if it's nothing at all.. I've been feeling very alone lately & when I am by myself all I do is think about my problems. My sleeping patterns have changed, I find myself staying up all night thinking and sleeping for atleast 9-10 hrs everyday. I feel like there's no drive in my life and it takes so much for me to just get out of the bed. I've cut myself before and it was a habit that I completely got rid of that's now coming back. I feel helpless and purposeless and when I reach out to my mom, being the "strong" woman she is, she makes me feel like I'm whining. I don't know what to do & I just need to know if this is weird for someone my age.. I'd like to hear from someone who's made it through depression.,