wow, myrophora, polish culture sounds a lot like british culture!
it is hard to 'go out' with friends without drinking alcohol.
i have sometimes found that it is very useful to offer to drive, then you are 'allowed' not to drink, so that may help if you have access to a car.
twice i have borrowed the car of my drinking partners!
once it was a very nice mercedes which i took over once i realised the driver who was going to take us home had a few beers already.
i didn't want to die on the way home
he was happy to take another beer from me in compensation for giving away his car key!
he was already drunk enough not to worry that he was giving his new car to someone he didn't know well...
now i am confident enough just to say 'no, i don't really drink alcohol' and am not bothered what people think, but before, it was a real problem. another thing that may help is alcohol free wine or cider or beer. it looks nearly like the real thing and tastes better.
what about lunchtimes at the weekend? do polish people drink alcohol even at lunch?
could you try a hobby or a sport where people get together for some purpose other than alcohol?
may God guide you