Sometimes that happens to me too, whenever I see a good loss on the scale I feel like I'm skinny and eat something bad. Don't be hard on yourself, you didn't gain weight from eating bad one day and you won't lose weight from eating good one day either. It's all about the repetition and how long you stick with it! I know the feeling of being disgusted with yourself, just eat something low calorie for lunch/dinner and drink lots of water. If you can get to the gym later, do it, but if not just start fresh tomorrow
Sometimes planning out meals helps me a lot like if I can cook the night before and put it in the fridge for something fast or just at least have an idea of what I'm going to cook and log it already in my food log, I will stay on plan better. Just a suggestion that works for me. Don't be hard on yourself for messing up. Just get back on it!
edit- do you think you might have symptoms of binge eating? or is this unusual for you? it's something I struggle with and many others in the 3fc community, if you feel like you can't control those binges or anything there are a lot of helpful forums specifically about that!

good luck