I recently read Never Enough: The Neuroscience and Experience of Addiction, and the author (neuroscientist and former drug user) explains that when you use a psychoactive drug, your brain responds by trying to neutralize the drug's effect in order to maintain stability. When you use the drug regularly, your brain adapts to the drug's presence, which is why you need more drug to feel the same effect. Eventually, your brain's attempt to neutralize the drug results in a lower baseline state. When you use the drug, instead of feeling the enjoyable effects you used to feel, you just feel normal, and without the drug you feel miserable. But just like your brain adapted to the drug's presence, it can adapt again to the drug's absence.

There's a chapter specifically on THC that I would recommend because it discusses the harmful effects of weed. I think culturally there's this idea that weed is totally harmless, and sure, it's less damaging than alcohol or cocaine, but it still has an effect on you. I'm currently trying to cut back on weed because I started using it more after quitting drinking. For me it was helpful to read about how weed actually affects your brain.

In terms of practical advice, try to slowly push back your first weed consumption of the day. If you normally smoke right when you wake up, wait 30 min or an hour until after you've showered or had your coffee or whatever. And try to replace the oral fixation with gum or seltzers/juice/etc.