Interesting, I found your site via your linked in account and was able to test what you were saying.
Interestingly I see that you rank as expected in all Google search sites except google.com?gl=us
When in the Google US results your site comes up in 48th place for your careers page. Not your homepage, this makes me wonder if Google is just doing some re-indexing of your homepage. How long have you noticed this? Sometimes with excessive link building or marketing it can cause a page to temporarily disappear for some keywords.
On the subject of keywords, you are using the the keywords meta tag, considering you have such little content on your homepage it is not wise to keep this tag and Google has said for many years now that it is not used and has been thought to be used negatively by Google bot.
If your ranking has disappeared for just a few days then be patient for a few more.
I noticed your name is not a madeup name it means army in Polish and it is also a Polish punk rock band. I do wonder if there is some confusion there when you look at the other results showing. But my instinct is that your homepage is just being recalculated for some reason. I see this happen all the time to my site when my rankings are about to change significantly in a positive way.
I would also look at putting your contact information on the homepage into rich snippets to help Google identify you correctly.
Also your blog has not been updated for 1 year
Also I see that your social media buttons on the bottom of your site do not go to the correct sites, it looks like it points to the social media site of the websites template creator?
I hope some of this helps you.