Unmotivated & Unhappy (Picture included)

I'm 5 ft 5, my weight fluctuates from 11-11.5 stone and I'm getting really unhappy :( I've tried diets, signing up to a gym, excercises and I just cannot physically seem to stick to it. I always cave in to the shitty foods and I've honestly had enough, I'm also a smoker and I'm so unfit. I need help!! I've had the same attitude for a year now I just honestly have no idea where to start! 😞 this is me on holiday recently about a month ago now. I used to be a lot smaller and have gained a lot of celulite I just want to be happy with my body but most of all be healthy and happy? Any advice?? Please!!!! Xxx