If that's the case
@Den***
, take
@Iv**
's advice and catch an early morning flight by Air Asia, Nok Air or Thai Lion Air to Udon Thani, take the mini van from the airport to the border, cross into Lao, get to the consulate and turn in your paperwork.
The next afternoon, get your passport, go to the border, cross back into thailand, go to Udon Thani and catch an early evening flight back to Bangkok.