I think therapy will be super helpful for you, and I'm going to talk from my experiences with MY therapist.
I understand what you're saying about missing the way you used to eat. From what I've worked through with my therapist, it's the ability to control what goes into my mouth. If I was having a bad day, if my abusive parents went off on me, I could gain control of my life again by eating an entire large pizza. If I was tired, if I felt like I wasn't going anywhere in life, I could eat an entire pasta bread bowl and cheese sticks. I could eat one, two three cheeseburgers because I wanted to, I was in control of how much I ate and went. That feeling of being full, of tasting that food over and over again, was what calmed me down.
Unfortunately, like more instant forms of self-harm, it's an unhealthy coping skill. You haven't gained any control by eating two large Double Double meals with milkshakes. All you've done is postponed your time to deal with it.
having surgery and having to be "forced" into a new way of eating takes this control away. You can't do what you used to do, so you feel like you're out of control.
You are worth so much more than gorging yourself on food. You are worth working through your feelings. You deserve so much more than what your brain may be telling you, and I'm so proud of you. ❤️