Hey.
I am sure your mind is having dark thoughts sometimes. That is the side effect of abusing mind altering substances, whatever pleasure you derive from taking them, the payback is always anxiety, depression etc You will find that prolonged abstinence from drugs will improve your mental health remarkably, and if, and it is a big if, you have any underlying mental issues, they can be treated. You can't get better whilst doing any drugs.
Stick around, you'll find lots of support here.