To anyone grew up bilingually or trilingually?... Does this only happen to me?

ur not alone in this. the great russian-american writer nabokov who spoke several languages from childhood (although probably all with a russian accent) wrote what i consider one of the greatest novels of all time (as did he himself, lol, but very few people agree with us) in which he images a utopian world in which russia and america peacefully merge into one bi- or even trilingual country (tri cuz all russian aristocrats spoke french at home) in which the best of both cultures had prevailed. and i suppose the only people who really appreciate this book are ones who have that same loneliness u describe, which comes precisely from belonging to a mixed kind of culture and personality that is at home nowhere. so i'd enjoy talking to u sometime about this. however, as for language, first, some people do get very bad at their first language--and almost all people i know who live in a foreign environment get somewhat bad at it. second, people do change which language they think in. however, all these things seem to vary enormously from person to person and have not been well researched by linguists OR psychologists as far as i know.