Fasting

You should talk to a therapist, you obviously have some sort of body dysmorphia.

It doesn't sound like you have a healthy relationship with food. As another commenter pointed out, therapy would be a good idea. You might also want to give this a read: All foods can fit in a balanced diet

I am a binge eater. I am mostly recovered but I do practice fasting right now to lose some weight I've gained.

If I restrict too long, it can trigger a binge. It sounds similar with what you've written here, you fasted more than a few days, and then your eyes did the shopping and you've some regret.

1300 calories is still a deficit. So, thats first. You still did a good job.

Going forward, would it be a good idea to have a very small snack while fasting? Sometimes just having an apple (or something) can help regulate your body so you dont buy the whole store up. Your body still needs nourishment.

If your goal is to go North, and you head east for a bit, doesn't mean you can't course correct and get back North facing.

You've not failed, and guilt for buying too much food, eh, is it really such a big deal? If you can't eat it all youraelf, maybe you can cook for someone else so it's not wasted.

You've not failed. Remember the positives and what you have done. 60 hours of fasting is impressive! Celebrate that! And please, remember, your body still needs nourishment, it's okay to nourish yourself

You're clearly battling some pretty nasty and fucked thoughts about yourself. That's never good mate, the perpetual self loathing gets us nowhere. But you know this, we don't choose to do it to ourselves.
You have probably heard 'seek therapy' enough, I'd like to ask though, is it accessible to you? What's the quality of care like?