Okay, so you aren't doing hard drugs.
However, the effect of cutting does release drugs in the brain that make you feel good.

"Physiologically, endorphins are released when we are injured or stressed. Endorphins are neurotransmitters that act similarly to morphine and reduce the amount of pain we experience when we are hurt. Joggers often report experiencing a "runners high" when reaching a physically stressful period. This "high" is the physiological reaction to the release of endorphins - the masking of pain by a substance that mimics morphine. When people self-injure, the same process takes place. Endorphins are released which limit or block the amount of physical pain that's experienced. Sometimes people who intentionally hurt themselves will even say that they felt a "rush" or "high" from the act. Given the role of endorphins, this makes perfect sense."

Myths and Misconceptions of Self-Injury: Part II | Psychology Today

This is just one source, but there are plenty of books on it.

So, yeah it's a big deal if you are cutting yourself. It's dangerous, and it's not healthy. Please find help if you can. I know you have to want help, and I hope someday that you do.

Love,
Marilyn