this will never end and the only choice we have is to give in and live in complete crazy world or distance and live in a world of moments of sanity but never quite norma
young fool, perhaps you could broaden that perspective to include more than those options. When we think it terms of either/or and only give ourselves 2 dismal choices, we can remain stuck because the two options we've allowed ourselves to see are not feasible for us. There are more choices.
You might attend 12 step groups like Al Anon, Families Anonymous, or Narc Anon to learn strategies to support you in finding ways to detach from your son's behaviors as well as learning from other parents who are traveling a similar path. You might get yourselves a private therapist well versed in substance abuse to learn how to set boundaries and insist your son is accountable for nasty behavior towards you. You might get a list of shelters in your area and provide that list to your son along with a timeline on him leaving if he cannot abide by the rules of your home. You don't have the power to change your son, only he has that power. If he refuses to get clean, you don't have to be responsible nor do you have to suffer with his behaviors......and if you do choose to evict your son, you can't predict at this point how you will feel or what will happen.....often when we stop enabling our kids, miraculously, they find their own way.
It appears your son is holding you hostage with his actions, choices and behaviors. It is your home, you get to make the rules. Look at what you are willing to do and what you are NOT willing to do. And enforce your rules with consequences. You've lost your power to your son....take it back.......then that feeling of being trapped will go away. You ARE trapped, trapped in a scenario in your own home where a drug addict is calling the shots.
You don't have to live in a crazy world your son invented........and you don't have to live only moments of sanity, you can have a whole life of sanity...... and no craziness......but you will have to make choices to change, to respond differently and to set strong boundaries. If you do that, the odds are in your favor that you'll get your life back and begin to enjoy it again. But if you do nothing.....you can pretty much bet that nothing will change..... then your statement above becomes a self fulfilling prophecy.