I'm glad you have managed to stop using drugs, I know it's a hard path.

I do understand what you were trying to do, but look at this sentence:

I’m sorry that I fed you substances that I knew were harmful to my own health.

In the opening line, you already are saying that it is harmful to your own health. I could tell you are talking to yourself. If you played it all in the second person, we would have understood with the last line.

Also, while re-reading it, I spotted a couple of typos. "your escaping" should be "you're escaping". "I sold drugs too" becomes "I sold drugs to". Don't worry, these are mistakes a lot of people do, especially when English isn't their first language. Heck, even those with English as first-language to these. But, it would not be fair for me to not point it out ;) We all learn from our mistakes.