@Amanda *****
alternatively you can exit Thailand to Cambodia, and apply in the Thai e-visa online system of the Thai embassy Phnom Penh for a 60-days tourist visa for Thailand. The processing will take about 4 days to one week, before the visa will be issued or rejected. It's easier if you just pay a Visa-Run Agency to take you to the border, stamp out of Thailand, stamp into Cambodia, turn around, stamp out of Cambodia and stamp back into Thailand without any visa (visa-exempt entry)