I know I'm going to sound really terrible for saying this, but I don't know why you posted this here. No one online can really help you. If you're truly concerned go talk to a doctor. None of us can diagnose you or do anything for you. You have to help yourself by taking a step and telling an adult, such as a teacher, school counselor, or doctor.
There's a difference between being depressed and having depression. I want to share these quotes with you from an article I read that I think explains it very well.
"I have those times where I start crying while brushing my teeth and I'm not sure why. We've all experienced this to an extent. You go through a patch where staying in bed all day isn't just the better option -- it's the only one. But as blue as things may look at that point, a lot of us are lucky enough to have the ability to say "I'm feeling depressed," as opposed to "I have depression."
There's a big difference between those statements, and the key word is feeling."
"Let's call my friend Hubert. Why? Because Hubert is a funny name, and nothing about this situation is funny.
Hubert went through some life changes. Some things turned out less than desirable for him, but all in all, Hubert would agree that nothing terrible happened to him. This is a common misconception about depression -- you don't have to have a traumatic home life, a horrible experience or witness the death of a loved one to become depressed. Depression has no rhyme or reason. It just happens."
School issues and family issues can certainly take a toll on someone. But from the sounds of it, it's one of those situations where that is definitely the issue, and solving the issue will fix things; it's being depressed not having depression as there's a cause and a solution that will mostly take away all symptoms. (assuming they actually are directly related to your issues.) I'm sorry that you have to go through that, and that is definitely a concern for you to talk about with a trusted adult. But self diagnosis is almost never correct, on any mental illness or disorder. You know yourself best, but you should leave it to the professionals to guide you through it.