Please help me, I want to fix the shards of my broken life?

Long story. I don't usually post questions about my own personal life via the internet, but I so desperately need help to fix my life just for the sake of my own health. I am a 15 year old teenage girl and I am wary of hormones, puberty and other changes going haphazard in my life. However, I do not think that going through long-term depression is "normal" for a teenager. Everyday, I feel depressed and severely unhappy. I have "friends" at school that are more of my acquaintances actually, my genuine friends are never at my school which is one of the reasons why I'm unhappy. Other reasons are that people usually tell me to cheer up and smile, but what the hell do those ignorant oafs know? I fear of socializing with other people because most of the time I make a fool of myself and they point out my flaws. Also, I feel like I'm trapped in my idealism. Most of the time I have a tendency to fill my head with false ambition about my so-called "future" and daydreaming of being happy. I daydream of being liberated from this perpetual sadness I'm going through. Least but not least, my "parents" don't act like parents. I will spare you the details, as it will already take up most of your time than it already does. My dad acts more of a goofball than your typical stern father, and my mother is irresponsible as she cannot take care of our household let alone herself. I don't want to add anymore details because I don't feel like talking about other weak areas of my life. Mind you, I didn't take all this time and effort to type this just to receive any smart-*** and just downright rude answers. I want to read some genuine down-to-earth answers that offer some advice to help me improve my life to benefit myself.