Do I have Depression? Please, please help me.

I am a 16 year old girl who thinks she is suffering from depression. Lately I have completely changed. I feel like the whole world hates me, and are laughing at me. I burst out into tears at random times; even if I just had a great day or experience. My relationship with my family is completely destroyed. I cannot have a conversation which them without screaming or crying. I feel like they hate me and regret having me. I also feel upset and sad. And I am ashamed to say whenever I feel like this I cut myself. I have 4 permanent scars on my wrist. As I do it I feel better but afterwards I hate myself even more. I really am afraid I might be crazy. I am not doing anything like drinking or taking drugs so it cannot be a side effect of something like that,
I constantly feel tired, and like to lay down in the dark, and sleep. My parents think I am being bullied at school and keep on threatening to call the school. I am not and when they threaten to do this it makes me more angry and more sad. I feel like I am in this constant loop. I think I may be depressed. I am confused because I thought if you were depressed you were constantly sad. But I have some happy moments when i am with friends or the rare occasions when I am actually not fighting with my parents. Which rarely ever happens.
Am I seriously depressed or just a typical teenager? The self - harm is what makes me worry. But I am not addicted to it. Please, please help me and give me some answers.
Thank you.

[Vballsetter]

Hi there. Don't worry, you are not alone. I experience something very similar a while ago, but I was bullied. :( From your symptoms, it does sound like depression, but don't diagnose yourself. What helped me with my issues (the sadness/depression/self harm) was to talk to my most trusted friend. She told me she was here for me and told me that my parents should know. After I told them, they got me to a therapist that I've been seeing for a while now. It really really helped and I think it will really help you too. If therapy isn't your thing or not financially possible, a school counselor might help or just talking to your closest family member or friend. Hope you get happy soon. Happiness seems 200000 miles away, but it is something worth achieving. :) hope everything gets better and you can be happy! :) god bless.  

[HelpMePlease96]

Thank you so much. You have no idea how much comfort that gave me to know that someone is or has gone through something like this.
I don't want to tell anyone because I honestly feel too embarrassed about it. I feel like I am just a typical teenager and exaggerating things. But If the situation does not improve soon I will confide in someone.
Thank you. :)