This surgery changes hormone levels, and it's a bit rocky for awhile. Our bodies have over 300 hormones, when one or more are altered our moods are greatly affected. And it's used to being insulin resistant - most everyone that is obese is suffering from insulin resistance and inflammation. Now add to that our abuse of food to alter mood, cope, and to socialize and it's a perfect storm. You have to replace those previous 'behaviors' with something else that satisfies those 'needs'. I believe exploring this in therapy or group support is a constructive option everyone needs to do. It is a HUGE process to make these changes, both in your head and physically as we have arrived in this situation after years of living with our collective experiences and relationships with food and people. Be gentle with yourself.
Sometimes it also takes medication, ongoing therapy, exercise, and time. And you can't look back, push on and know that the physical health you get with this surgery is amazing. Good luck.