Welcome. Both my kids are addicts, my son is a pot/alcohol addict and my daughter's drug of choice is meth (tik).
It is a nasty, horrid drug. But it is not impossible to get clean and sober from it.
Letting go of our addicts means not being there to "help" them while they are using. When I helped my kids, I actually provided a "soft landing" ... they never felt the pain of what their using caused. When they used food money on drugs - I gave them food. When they sold/ruined/wrecked cars while chasing drugs - I gave them another car. When they lost/sold cell phones - I gave them another cell phone. When they needed a place to sleep (because they couldn't work due to drug use) - I gave them a place to sleep.
If a drug addict can have a hot meal, a warm bed a roof over his head AND his drugs... why would he ever stop?
It took me a while, and I still struggle some days, but I finally stopped doing the things for my kids that they COULD do for themselves. They had to live IN the pain they caused by their own use. Yelling, crying and caterwauling the whole way.
Alanon helped me be strong about my detatching and helped me to understand I can still LOVE them, even when they are still using. My daughter is sober today, and my son is not....but I love them both.
I hope this helps.