Big fight with boyfriend led to emotional eating!!

Read a book. Drink a gallon of water. Do sudoku. Solve a Rubik's cube. Play the piano. Do 20 push-ups.
There are literally thousands of things you can do besides eat.

You chose to eat and are blaming it on the boyfriend and "stress."
Hold yourself accountable.

My wife wanted to train with me but I told her no for years.
Finally I agreed to coach her with the stipulation that if she ever took any order I gave her in the gym personally and was still angry about it at home or took any argument at home into the gym then she was out of the program.
There were close calls but she did it.

If you cannot separate "stress" from "eating" then you may need to see a therapist or something.
Otherwise it is a choice.

As @quiksylver296 says, if nothing else then just acknowledge it and move on.
But stop rationalizing and blaming "stress" for your behaviors or you will be unlikely to modify them.

Walks, reading, mediation, etc.
Or go for the full over haul and get a new boyfriend!

Almost everyone who is overweight got to that point for psychological/lifestyle reasons. Emotional eating is common for a lot of people (I used to do it too) if you want to lose weight in the long run, it helps to be aware of your triggers. Your boyfriend didn't make you eat/drink unhealthy food but at least your aware that you're prone to emotional eating. There is nothing you can do about it now so there is no point beating yourself up, just keep going and don't let this take you off a healthy path. Try to find some coping mechanisms and use them when you have cravings. It really helps if you look at food as fuel, not medicine. I'm sorry if I came off harsh, honestly just trying to help

Sorry to hear about the fight. The important thing is that you realized what you were doing. It is never too late to make changes and do right at your next meal. Sometimes I eat like a crappy breakfast and was like "why did I do that?" Then I can make it right by lunchtime and dinner by eating something more healthy. Life is about balance. Forgive yourself and jump back on the healthy bandwagon right away. If you don't want to work out today do it tomorrow. Or do something else. Maybe go dance?

As for stress, I do what I am passionate about and that is drawing. I love sketching and watching tutorials on how I can improve my skills. I also like looking at pinterest, beautiful art, sometimes I may reach out to a close friend to talk about the situation, hang with my bunnies, read a book, drink tea, look up more ways I can incorporate healthy habits into my life, there are a lot of things you could do.