I am happy to see that you are currently learning Swedish! I thought I was the only one here (not learning, but speaking) =). To answer your question - my situation is like your Swedish friend's. Normally, when I am home in Sweden, and mostly engaging in Swedish conversations, my thoughts are in Swedish. When I am in school, which is in English, my thoughts are mostly in English. I am in Turkey now, and most of my conversations are in English. I still tend to think in Swedish when I am alone, but when I am with others, English is more the language running through my head.