I feel sooooo bad an guilty

I had 2 weeks without no junk food no hot cheetos I would eat them every day I decided to change my diet and I did which I’m proud. Again it’s been about 2 weeks with no junk food what so ever no late night cravings or eating late. But today i felt like a failure I had pizza, then later that day I had kfc , then chips then just now I ate a slide of pizza like how? I was doing so good and I failed 😫😫😫 it was so much today