I’m really confused and concerned about this please help me and tell me what do I need to do 
I’ll really really appreciate that!
Far better to ask the people in the college admissions office than to rely on opinions here. If different colleges have different policies, you wouldn’t be caught off guard.
Usually, it depends on the language of instruction at your high school. If it was English (and your transcript reflects that) then no, you don’t have to take TOEFL. But if the primary language of instruction was something other than English, then yes, you will probably have to take it. If you primary language at home is English, you may be able to avoid the test, but usually they want to see proof of English proficiency.
The issue is not so much your nationality but whether you’ve been educated in English-language schools. If you’ve been educated in english, then contact EACH school to get a waiver.
I agree with @GMTplus7 . Every school seems to handle this differently. Contact your targeted schools.
You absolutely need to contact each college and university on your list, let them know that you are a US citizen educated abroad, and ask them what they need you to do. Do not be surprised if each place tells you something different.
I’ve never heard of an American citizen living abroad taking the TOEFL, but it may be because my son attended an international school that was taught in English. Curious to hear what kind of responses you get.
I have expat colleagues w children born in the US, educated abroad, and not educated nor proficient in english.
Depends on your circumstances. If mom and dad are Americans living abroad, speak English at home, etc, that’s one thing. But lots of folks have US citizenship (or dual citizenship with another country) who have never lived much in the US. For instance, if you’re born in the US to S Korean parents who are in the US for grad school, you can have citizenship, but you might not remember a thing about the US, English wouldn’t be your language at home, etc.
I wouldn’t assume that “language of instruction is English” would mean a lot for TOEFL purposes. There are some countries where basically ALL the private schools teach in English, but most people still can’t speak anything close to good enough English to deal with a US college. My nephew went to an English language boarding school in India and still had to take the TOEFL. As far as I know, all “English medium school” kids have to take the TOEFL, unless they’re in a true int’l school.
Incidentally, in some countries, many perfectly reputable private schools stick “International” into their name – “Oxbridge Harvard International School” etc – and teach in English but are not true int’l schools, which actually means accredited by an international body such as the Council of Int’l Schools, IB, etc. I’d think that most countries don’t have many true int’l schools.
Speaking English at home is one thing. Having a command of Academic English that is strong enough to handle the demands of university-level studies is an entirely different thing. The TOEFL, IELTS, and other proficiency exams attempt to get at that piece of information. So if you do find out that you need to take the TOEFL (or IELTS, or another proficiency exam), and if you end up with a score that is good enough to get you admitted, but low enough to get you placed into an advanced ESL course focused on university-level reading and writing, please do yourself a huge favor and take that class. Classes like that don’t exist to punish students like you, but rather to give you a chance to quickly get your language skills to where you need them to be.
If your reading/writing scores are low, it is beneficial for you to take TOEFL, on the other hand, if your scores are high then I am not sure if TOEFL is necessary.
Cornell’s policy (different for each school):
If paying the money to register for the test is not a problem then go ahead, you need no prep, I went unprepped and scored a 113/120, it only tests very basic english and if you prep for it and score around perfect then there are awards too, research it.
“Or where English is an official language”? So that would include India, Pakistan and Sri Lanka? Hmmm. Maybe. But I’m not sure they thought that one out very well 
Perhaps Cornell has such high standards that they wouldn’t admit anyone who didn’t do super-well on the CR section of the SAT anyway … but there are an awful lot of countries where English is “AN” official language without being the first language of a meaningful number of speakers. A lot of former colonies with a multiplicity of languages use English as a lingua franca (as it were).
I do recommend that you spend some time with an iBT prep book before taking that test. The some of the scenarios and vocabulary on the exam are specific to college and university settings. Reviewing that vocabulary, and thinking about those types of scenarios can be very helpful.
THANK YOU ALL!!