You gotta do it every day. Running is much more mental than physical. Pick a distance to do every day then make sure you complete it one way or another. 3k for the first week, 5k for the next week, etc. If you have to walk so be it, but complete your miles. Just keep at it and you will get there. I firmly believe that the reason Thais run so much is to build mental toughness as much as it is to build physical strength/endurance. Hence, as Kero said, your trainers will know how much you've been running based on how you fight. If you are timid or inconsistent when clashing with an opponent, they are gonna say you didn't run enough lol. I don't get the whole runner's high thing either and have a strong hatred for running (especially fast). It's necessary though and will teach you to break through moments of weakness. Just get your miles/Km in every day, don't worry about the pace. Good luck and enjoy your trip to Thailand!