I have been posting some of my pictures on a website that features the best photos of food on the internet. I am not a photographer and I am grateful when good light enters my kitchen so I can take decent photos of what I consider healthy and nutritious food. It's nice when someone likes a photo and posts it online. I also have to say a lot of the pictures get rejected. Not sharp enough, poor lighting, poor composition, food, etc, etc. I don't consider these pictures failed pictures, and I like to know that they could be sharper, have better lighting, white and black balance, etc.
That made me think of how we view results. Oftentimes, we want to see a certain result from our work. A firmer butt, bigger shoulders, lower body fat. If we don't see it, we may consider it failure and jump onto the next thing - a new workout program, a stricter diet, a more flattering mirror. In fact what we need here is not the feeling of failure, but rather the chance for feedback: diet not strict enough, too many sweets, too many skipped workouts, not enough water. With definite feedback, you know what to focus on, rather than throwing the baby out with the bath water. I don't throw out my camera and invest 2 grand in a new one, because I had the wrong background for my photo. I would strongly advise you against stopping your diet or training, because you didn't get the results you expected. Analyze, change, adapt, repeat, and then see yourself reach your goal.