If you have only been in the US for 3 months since 2001, then you are deemed to have abandoned your residency here as you clearly are not a resident, but live in another country. What will happen is that when you attempt to pass through customs, they will realise that you haven't been here all this time and that therefore you no longer have a valid residency card.
A reentry permit is separate from the issue of abandonment. How old are you and what are the circumstances that caused you to leave the U.S.?
You should return to the U.S. and see what the customs people do. They will let you in the U.S. but may refer you to court. In that case you have to fight for your green card. The answer does not change even if you received the reentry permit.