I just arrived this morning via boat at the Belize/Chetumal boarder. My plan was to fly to Mexico City on a flight leaving about an hour from now. And then catch a night bus to Oaxaca. At the chetumal airport it was pointed out that they didn't stamp my passport just my ffm. Should I try and fix this at the Mexico City airport or do it in Oaxaca. I've heard they check passports at military checkpoints. My Spanish is decent enough to get around but not nearly good enough to explain this oversight. So what are my options? I would still like to make it to Oaxaca by tomorrow as I am meeting my girlfriend and our professor but I know this immigration thing may take a while.