When it comes to filing taxes as an American living abroad, it can be a complex process, and you may need to seek assistance from a tax professional who is experienced with international tax laws.

One option is to find a Certified Public Accountant (CPA) or Enrolled Agent (EA) who specializes in international tax issues. They can help you navigate the complexities of filing taxes as an American living abroad and ensure that you are in compliance with both US and Portuguese tax laws.

You may also want to consider reaching out to the American Citizens Abroad (ACA) or the IRS's Taxpayer Advocate Service (TAS) for additional guidance and support.

It is important to note that if you are a US citizen or green card holder, you are required to file a US tax return every year, regardless of where you live and where your income is earned. The rules around claiming the Foreign Tax Credit and other benefits can be complex, so it is important to seek the help of a qualified tax professional to ensure that you are meeting all of your tax obligations.

I hope this information is helpful. Best of luck with your tax filings