Post-Op regret is usually because you're in the phase where your surgery is all sacrifice with very little gain as you're still heavy.
Old bad habits are still wanting to be satisfied, you're on a restricted diet, it's tough.
This surgery is not a 1 week or a 1 month thing. It's a lifetime change. If you got it not knowing that, you're probably going to underperform in terms of your weight loss goals. If you can't manage some degree of food intake self control for the first few months while you're healing, you probably need emergency psychiatric intervention as this isn't something you can screw around with and not risk a potential blowout or tear.
When you go this done you signed up for a new life. Welcome to it.