It’s like being in withdrawal but seemingly forever
This is what has stopped me from sticking to sobriety for more than a few weeks at a time. I have more years on Earth than you (and thus more time in a chemically induced state) but yeah, I absolutely relate to what you wrote. I'm concerned that I'll never be able to really get 'clean' because the hole is now so deep that I don't know if I could ever return to any sort of baseline/normal state which wasn't just despair. Perhaps years of abstinence and healthy living would eventually do it, but I don't have the inner strength or stamina to do that.
Also, OP's experience through this thread really drives home a difficult truth: You cannot protect or help people by telling them not to take drugs, because they will never know the damage it can cause until they've experienced it for themselves. The best anyone can do is offer practical harm reduction information. That's why I think BL has genuine value - "just say no" has never and will never stop people using and abusing substances.