Hi, new to the forums-not to the app

HI,
I'm 4'10", married for 17 years, have two teenage daughters, and two dogs and a 11 year old diabetic cat. I Joined My fitness Pal quite awhile back when my cousin said she lost weight by using the app when her doctor said she has slow metabolism. I have tried just about everything-no carbs, no white food, hip hop abs, insanity workout, wii, walking, dieting, and everything in between. Been trying to fit from an 8-10 to a size 4. I only drink water, I exercise almost every day, watch what I eat, walk every day, what am I doing wrong? Any advice would be truly wonderful. Thank you :)