i know how bad this is to hear, but literally anything you take every day will stop working sooner or later and now you still have adhd but now a drug problem too. drugs are a terrible way to address any chronic problem, a real last resort - they can be a good way to chill out for a bit if you're exhausted or if you just need a change of perspective, and they're certainly cheaper than five star hotels - but don't underestimate how long cannabis tolerance can take to fade or how much even a mild dependence (if you have a tolerance, you have a dependence) can disrupt your life, especially sleep, especially if you are adhd. learn to live with neurodiversity (there is some good advice in other people's comments - don't eat sugar or processed food much), then get high now and again for a break from having to - that's my advice, although how relevant it is for you i have no idea. also, t breaks need to be looong. if you have a high tolerance, really looong. thc gets dissolved in the fat in your body and takes ages to leech back out. you'll see what i mean.
whatever it ends up taking, you'll get the hang eventually and life'll get a lot easier. honestly, you'll already feel a lot better after a t break. do it now.
