So sorry to hear that you had a bad day. It happens to all of us from time to time. You are not alone. I completely understand the feeling and sometimes I can even think about how I'm going to feel afterwards and still do it :-(
However, put it behind you. It has been a bad day. Do NOT let it ruin everything. You've made a commitment to this change so accept that it won't always be good and move on. It won't necessarily make you put on this week (or stop you losing) but if it does, just accept it and look forward. You are not a failure for one day but don't let it spoil the rest of the days.
However, maybe tomorrow or another day you could look at your triggers to see whether there's anything that you can do to try and prevent this happening ?
Big hugs. I wish I could say something more to help.
Anytime. You need to know that you're not alone. And you need to stop feeling so guilty because it's destructive. Whatever you've eaten, you've eaten. Now you've admitted it (to all of us here) which is really hard. Tomorrow is a new day. Accept the consequences and work hard to compensate. But don't deny yourself syns - that'll just start the cycle again.