My plan was to go to Poland, get a service desk job...
A couple of problems here. The call center job will pay at most 400 Euro a month, 500 if you are exceeding lucky. Without specialist knowledge of IT, it will almost certainly involve cold-call sales or low level collections, neither of which will enable you to bring in a significant amount of money on commission.
That will enable you to live like a monk at best. Forget about savings. And, as Monitor pointed out, there is little in the way of job security.
...learn polish...
Next, learning Polish to the point that you would be able to operate on the Polish job market will take you several years. Probably closer to five or six if you are working full time in a call center.
and after that try to get a better job. But I guess it's an inflation of educated people in Poland too.
Yep, that's right. Even after learning Polish and work in a call center for 5 or 6 years, you will end up with little salable skills or experience that you can sell on the Polish job market. There are many people with higher degrees stocking shelves at Tesco in Poland, and even working lousy jobs in call centers.
Dammit, I really messed things up as a youngin' dropping out school to start working instead!
Yes, you really screwed up, but fortunately you can still repair the damage and eventually gain the qualifications to pursue a decent career path.
Perhaps I can get my "gymnasiekompetens" on distance, while living in Poland.
It's going to be A LOT easier for you to repair the damage in Sweden than in Poland. I would strongly advise you not to come to Poland without a university degree that means something on the Polish job market (and business administration is not very useful at all).
Also, if you don't want to pursue the college route, you could back and get an education in a trade like electrician, plumber or mechanic. Not very useful on the Polish job market, but can enable you to make a rather good living if you are willing to work on offshore oil rigs in Norway or Sweden. Talk to a career counselor.
Sorry, but I find your plan of moving to Poland in the near future unrealistic and unworkable. Even under the best of circumstances, you will miss out on the chance of pursuing a decent-paying career, and you will end up just as old if you spend the next six or seven years in Sweden, but without a degree, trade or anything worth much on any job market anywhere, Poland, Sweden or elsewhere.