Int’l travel 18 days away no passport

Hey I’m traveling out of the US for the first time and just realized lost my passport I got in 2017. My flight to Mexico is on 5/3 but none of the passport centers in the area have appointments so I’ll have to travel at least 4 hours after booking an appointment (I have no car so I’ll have to rent a car, pay gas, and drive right back) - has anyone else have to do something like this and have been successful? Should I just do it online?