Why does it always get worse?

Every day I wake up from a previously horrible day, and I try to stay positive.  But then…comes this force that drains my energy, and all the hope I ever had.  I fall deeper and deeper every day, every time I try harder and harder to stay up.  As for my academics, I work hard (orgo. chem in high school), but then sometimes lose it all in the middle of my classes or when I am doing homework.

I look at other students who are always truly smiling (unlike my fake smile), and they seem to enjoy every second of their lives. And I…I just sit in a room, and study, and work, and go through the days depression symptoms.

I have tried to come home and write a list of the good things that happened that day, but then the negative instantly crushes the positive, if that makes sense.

After three years of this stress, depression, and wish to go away and hope to get a good life (ironic), I find every bad thing that happens in a day as bigger than it actually is. I instantly tip over from the breeze; something so light takes me down further than ever, because over time I have learned that no matter how much I try, I will only go down even farther.

Any recs. on what to do? I feel like just going away, and going to this dark, calm, peaceful place, yet at the same time, I feel like living up to my academic potentials or doing what I love.