"43 yr old female. i started phentermine 37.5 mg once a day,  on march 14, 2017. i lost 10 pounds as of april 12, 2017. today is april 27, 2017 and i have lost 18 more pounds in 2 weeks. total of 28 so far. i have no appetite at all really. but i was starting to get dizzy, and nauseous. severe stomach pain, so i force myself to eat small meals. i do notice that i&#039;m constantly thirsty. easily agitated or annoyed also. but other than that i like the results"