First Language - Second Language = Native Language - Foreign Language?

Ok, here I am again, back in Germany. I tell you this: My brain still "lives" in English. I am back in my native country, surrounded by my native language, and yet, it feels weird. On the plane back, I only talked English to the staff and the other passangers because it felt more natural. I told my brain, "You better get used to German again once we've landed."

Well, I am able to talk in German, and I have been writing and chatting in German regularly with friends and family while I was in the States, but man, it's an act of concentration to not slip into English in an oral conversation!

Actually, when I was on the phone with my sister yesterday, I read a comment on Facebook (in English) and continued talking to her in English as a result...until I noticed it some sentences later!

My first language at the moment is clearly English. I have no problem with it (maybe some people around me might because they don't understand me if I speak English, but again, I don't). I love the English language and have, in fact, always liked it more than my native language, from the moment I first came into contact with it back in elementary school. Indeed, I feel as if I'm visiting a foreign country right now. Strangely out of place...not belonging here. It's more than just my first language that has changed, I have changed.

I would love to hear from other people who have spent some time in a foreign country if they have had the same problems concerning their spoken language once they came back. I don't remember having problems with it when I returned from Spain after a four week internship there, but then, it's quite some years ago and maybe I have just forgotten about it.

So, what's your experience with it?