What should I do since I still have my yellow packet and I have no arrival stamp in my passport?

As you were supposed to give the packet to the officer at the port of inspection, you should arrange with Customs and Border Protection at any airport with international flights to give in the packet. If they have not already created a record of your arrival, they can do so at that time. Due to the limitations of the Lawyers.com Forums, Alan Lee & Arthur Lee, Esqs.’ (the "Firm") participation in responding to questions posted herein does not constitute legal advice, nor legal representation of the person or entity posting a question. No Attorney/Client relationship is or shall be construed to be created hereby. The information provided herein by the Firm is general, and requires that the poster obtain specific legal advice from an attorney. The poster shall not rely upon the information provided herein as legal advice nor as the basis for making any decisions of legal consequence.