Lifestyle changes

I have been depressed these past few days. The reason is because I am depressed over this diet. The fact that I can't put any bit of sugar in my mouth without my sugar and insulin increasing which leads to me gaining weight. Even natural sugars like fruits I can't even  handle. The only fruit I can eat with no increase in sugar are lemons and avocados. Which makes me really sad because I am a sweet tooth person, I love candy and sugary things. And because all of this it finally dawned on me that I will have to be on this diet for the rest of my life. It's not a diet its a lifestyle. I will have to live this lifestyle my entire life if I want to be thin. And that makes me depressed. I may become ok with this reality some time down the road but right now it just sucks. I can't see a world without ice cream, pizza, and Chick fil a. Someday I hope I'll be at peace with my new lifestyle but I am not today. I was thinking about doing Atkins however Atkins let you eat more protein then Keto does and that's bad because if you eat too much protein then it can turn into sugar which will cause weight gain. Uh, I just want to eat a muffin and be happy, but instead I'm sad and eating celery.