Undergraduate / "I began to cut myself daily..." - My Personal Challenge Essay [4]

Critique this please, I really want to improve on my writing. We had to write an essay on a personal challenge:

I sat there and watched it drop onto the shower floor, staining the water red as it diffused into the clear confines of the ghastly drain. A few more drops, drip drip drip, and the water changed from clear to red, clear to red. It didn't hurt anymore, it didn't matter anymore. I stood there numb and emotionless, as I trailed the last few drops of blood drip to the shower floor. I turned the water off and opened the shower door and caught a quick glimpse of me in the mirror. Who was I? I didn't even recognize me anymore.

It was probably six weeks into 7th grade and I felt as though my world was coming to an end, I just began to give up slowly, till the point of despair. The world crashed down on me simultaneously and I didn't take the pressure well. I recalled hearing people talk about cutting themselves, and I thought it was stupid, why would someone inflict pain on themselves? An afternoon came around, and my thoughts were pushing me into a dark hole. I stepped into the shower and grabbed the razor. My heart was thumping, I could feel it beating through my chest, the blood pulsing through my veins. What am I doing?

Drip. Drip. Drip. My thoughts went down the drain along with red water. It felt...good, no, relieving. It was as though my thoughts evacuated my brain, escaping through my pores and this cut. It went on like this for weeks whenever I'd encounter a problem or thought I disliked. It was solving my problems, or so I thought. I began to cut myself daily just because I liked the way it felt, it was invigorating. It didn't hurt as much as I thought it would and I didn't keep anything bottled up, it flowed away from me. It became an addiction, and soon afterwards, it didn't help, just added on to the depression I was facing.

"Promise me you will never do it again. If you do, I will never speak to you." My best friend had gotten hold of my journal, and I'd never seen him so upset. He looked at me with a stern face, eyebrows in, no dimples, looking straight through to my soul. But he couldn't hide the tears. They welled up inside his eyelids, and he fought with every inch of his body to keep it in. He put into perspective for me that I was hurting others around me, including him. I couldn't stand losing him, nor seeing him like this. "I promise." Promises were sacred to us, we rarely made them, and when we did, we kept them.

Every now and again I'll have an itch to grab that razor, to slice it across my ever so eager skin, to watch the blood drip, drip, drip onto the shower floor, change the color and tunnel down through the drain to wherever the sewer pipes lead. But I won't. I look back on it now and saw how stupid and reckless I was. It was a challenge for me not to pick up that razor, but now I can say that I'm pretty content. To this day, I haven't broken that promise.