you are probably going to need to consult with a tax professional.
we don't know how many years you earned income while living in Mexico and each year stands on its own.
The tax laws provide that if you meet either the bona fide residence test or the physical presence test you would qualify to use the foreign earned income exclusion. Form 2555 IRC 911 and PUB 54. there is a maximum each year that can be excluded from taxation by the US. There may also be an exclusion or deduction for housing. Foreign taxes paid on the excluded income do not qualify for the foreign tax credit. Income excluded for income tax purposes is subject to social security tax if work is performed outside of the US by a citizen of the US as an employee for an American employer, or regardless, if the work performed is recognized as employment under an agreement entered into under 233 of the Social Security Act (IRC 3121(b))
Use of the Foreign Earned Income Exclusion is voluntary.
