What you are saying here confirms that it absolutely isn't anything to do with the dosage - which, incidently, it rarely is. Though there will always be the exception to the rule when it comes to maybe needing a little more naltrexone, it usually has more to do with action than dosage. And the fact that you are not getting the buzz means that the brand of naltrexone is fine too.
Here is the thing with these (any) medications. They do not stop you if you are insisted on pouring the drink down your neck. With naltrexone, all it does it block the endorphin rush that means you are compulsively being driven to continue drinking.
With that blockage in place, there becomes the question of putting some action in to learn NEW habits in place of the old drinking habits. This takes time and patience, because most all of us have ever really known is drinking.
Here is a good question for you: why do you feel the need to get drunk? Is it a way that you cope with stresses of daily life? Are you looking to escape something?
The answer to this, whatever it is, will tell you that in place of alcohol you need to be looking to change your lifestyle in other ways. For example, if it is a coping technique, then you will need to learn new and more healthy/appropriate ways of coping.
If you do nothing but remain compliant, then the good news is that eventually your brain will realise that getting drunk without the buzz is a pointless thing to do, but how long would that be? The longer it goes on, the more likely you are to eventually convince yourself to not take the tablet and you will be back to where you started pre-naltrexone. This treatment is a marathon, not a sprint. It took me 8 months to complete become indifferent to alcohol.
And when it does happen, you will still be left with having to find something to fill the void. For nearly all of us, alcohol has filled some kind of void - whether that was pain or boredom. Take the alcohol away, and there is a huge big void that you can fill with lots and lots of GOOD things.
Take this as an opportunity which is both exciting and exiting in equal measure. It's like an etch-a-sketch? (Remember that, ha ha!). You have the opportunity to shake away the old remnants of something you were happy with - drinking - and redraw a new future for yourself that is far, far, far more rewarding that your old one!