Do you have a US Passport or Certificate of Citizenship? If so, then you are, indeed, a US citizen and it should be an administrative matter for USCIS to correct its records. If you do not, then you must take this matter very seriously, and consult with an immigration lawyer on this.
It is puzzling that USCIS cannot find you in their records. Depending on the adoption porcess, and the US laws in effect at the time, you may have acquired US citizenship, or you may have entered the US as a permanent resident. But if USCIS has no record of your lawful US entry, you could be in a jackpot.
Check with your mother concerning the immigration papers and related adoption papers. Try to find the Passport on which you entered the US and see what was stemped in the Passport on your entry.
Again, if you do not have a US Passport or Certificate of Citizenship, you should take the time and effort to consult with an immigration lawyer about this.
Note: This information is offered for educational purposes only; and, is not, and should not be considered, legal advice. No attorney-client relationship is created unless we have a signed engagement letter.
Answered on Jan 16th, 2013 at 11:48 AM