I'm really healthy. I've never broken a bone. Never had major surgery (except for a hernia at 6 months old). And only ever got stitches once... when I had a vasectomy: I got two stitches. But I am honestly scared of that craving you describe. If I ever get seriously ill, or need major surgery, the opioids worry me. I like drugs. I've done a lot of MDMA and mushrooms in my life, and have enjoyed LSD several times. But those are recreational and non-addictive. Experiencing that craving for a drug would terrify me, as well. I hope never to experience it. Congratulations to you on recognizing it, and turning away from it so powerfully.
However much I want to front as an eidolon of willpower, I can't say for sure how I would have handled that craving without the support and transparency between me and my family. They've been caring for me since the surgery, and the accountability to my parents is a huge factor in summoning the willpower - I wasn't just doing it for myself. I also don't know how I would've done if I hadn't just quit smoking. I have a feeling it'd be easier to develop another addiction if I was still embroiled in another.