I don't mean to complain! Just need some advice. 

I'm 16 years old, going on 17 in May. I have horrible grades, all c's and an F in math. I can't get myself motivated, i'm depressed all the time although when i'm around others I can laugh and jokes and all that. When I try to study I can't concentrate for too long, and can't remember much. I'm horible at math, science and history, but i'm really good at Literature. Most of the time I feel worthless. I'm in 11th grade, and I have African parents. If you don't know what that means, they're basically asian parents times 2. I hate dissapointing my mom, but i don't know what to do, I just can't get motivated! I know that this is my life, and I need to take hold of it, but I can't get myself to do anything. I need to study, I can't concentrate or remember anything. I need to lose weight, but I have no energy to excercise. I'm tired all the time, and I really wish I had someone to talk to. For the last few years, I've been holding everything in and I don't really know when it's gonna explode, but it won't be pretty. The purpose of this blog is this. I know I need to get my life together. I need motivation, and to get a plan going. If any of you have any interesting college majors, that'd be really helpful! If you have any studying tips, or ways to stay concentrated, and how to stay motivated that'd be really awesome. I just need help.

Thanks for reading, and I'm really looking forward to the replies :)