Am I really depressed, or just over reacting?

Hi, there. I wanna start out with thanking you guys before hand for answering, it does help.

Anyways, I'm 13, and will be 14 in January.
I came to this site because I think I might have depression, but I'm not sure and just confused.

I want to be reassured that I'm not just lying to myself and trying to put on a show, but I can't give myself an answer. I don't really think that I have any reason to be depressed, since life has treated me mostly well.

My parents are together. They are kind and uphold honesty, which is probably why I'm afraid of lying to myself and everyone else. My brother is amazing and fun to be with. My friends are caring and reassuring, and one in particular asks me what's wrong when she notices me acting strange.

All in all, life is good. Except for the fact that I cry myself to sleep a lot and feel like I'm doing bad things by thinking I have depression, and I think it's affecting how I act, and it might be me trying to put up an act.

I think these really sad feelings started just last year, in 7th grade. My best friend had to leave the school since she was moving, and she's now home schooled and lives half an hour away.

Before she left, I didn't have a care in the world. My best friend from elementary school, who had been with me since kindergarten, had to leave in 6th grade, and while I was really sad, my other best friend came to the rescue.

When I had her around, I didn't have to fit in. I didn't have to act like everyone else, because she was right there by my side, and she liked the stuff I did, so we could enjoy it together. Then, she left. 7th grade was a very bad time for me, to say the least. I was a wreck.

Up until then, I was well behaved, I got good grades, and I never wanted to be bad. 7th grade, that changed. The first quarter, I cried at the very mention of her. I got over it, but felt so alone. I felt like I needed to fit in, to change myself, just to gain friends, like if I didn't no one would like me.

I'd had bullies up until then, but it really hurts when your "friend" became that bully. My true friends were there to support me, but I felt that even though I was surrounded by people willing to help, I was utterly alone in a dark chasm I couldn't escape.

That was the grade I got my first detention, and I was so traumatized by it. I had always wanted to obey the rules, to not get in trouble. Now I was known as the kid who got a detention. I was just shattered, yet I couldn't bring myself to tell anyone, since I was afraid I'd be judged, that I didn't have a right to feel this way, since so many other people suffer more than me.

I used my drawing as an outlet for all the sadness, sorrow, and hate I now had, but I was petrified at the thought of someone seeing my drawings. I fell apart, and started to think about suicide. I thought, "It's the only way out. Your useless to this world, and no one will care if you just leave." But even though I thought about it, I couldn't bring myself to do it, since I was still afraid of them judging me for it.

I finally came to the last straw. I thought if I didn't do it now, I wouldn't ever do it. So I planned to jump out my window, since my room is on the second floor of my house. I piled all my heavy things in front of my door, wrote a note, and was about to slip it under the open slot of my door when I heard a knock. My dad called out, "Open the door!" So I did, removing all the stuff, and opened the door to my angry looking dad, and my brother, holding a piece of chocolate cake for me.
I made the excuse that I had been cleaning my room and took the cake gratefully. I haven't told anyone about it since.

This year is better, but my past still haunts me. My nightmares are getting worse and more vivid, ranging from my family getting killed by a science experiment gone wrong to a doll trying to sever my thumb to a getting kidnapped by a rehabilitation and a friend of mine trying to kill me with some sort of green liquid in a syringe. I don't know if these feelings are causes of it, but I added them just in case they were. I'm starting to push people away, just to turn around and feel alone, which makes me feel horrible.

Whenever a friend asks what's wrong, I avoid the question or don't respond. I'm too afraid to tell my family or friends or to seek medical help because I don't want to be judged if I was over reacting, because I just want to fit in and not do anything else wrong.

I looked up some depression quizzes and took them, and they said I have medium to severe depression, but I don't know if I truly answered honestly or if I was just over exaggerating.

Am I just being a drama queen, or is this really depression? Please help!