Euphoria during and after drinking

I drink about half a liter of vodka every Saturday. Previously, I used to drink a similar amount of alcohol in beer. After some time, I noticed a positive change in that I no longer vomit after drinking. On the other hand, drinking no longer gives me the same euphoria as before, and after drinking, I feel not euphoria but tiredness. It’s not like I have a stronger tolerance and larger doses will help. I still pass out after a similar amount of alcohol as before. It even happened that I didn’t feel any phases, and suddenly passed out. It improved a bit when I switched from beer to vodka. There used to be a better phase after beer, but lately, it’s been after vodka. I feel positive effects of alcohol during drinking. However, I still feel tired after drinking, which I didn’t feel before. Even if I passed out, I used to be able to get up quickly. Now, I don’t feel like it. What’s happening? Would a break from drinking help me regain the original effects of alcohol? How long would this break have to last?