in Bangkok. I was at a conversational level after 4 months there and with the base I got from them I got to fluent in a years time.
Study and practice outside of school all the time and use YouTube to learn phrases, tones and the alphabet. The more you're around the language, the easier the tones will get.
But because Thai is a tonal language, which English isn't, if you spend 90% of your time speaking and hearing English, nothing, except the basics, will stick.
just answering the question you asked. That is what would have happened if you didn't call to confirm. They need confirmation from the hotel and if they don't get it they cancel the booking. Same with flights.