I have been keeping a low calorie diet for 3 years how come im not getting any thinner!?

im 5'4 116 lbs and 3 years ago i was 147 lbs and i kept restricted calories very slowly every half a year or so. when i reached my plateaus i would restrict more calories and make my workouts harder..but now im eating 1350 calories a day and i want to lose 6 more lbs and my workouts are already very hard for me and eating less would just be miserable what should i do!?