Hard to do, but remember you are choosing to gain weight back. You may not realize it, but everything you put in your mouth is a choice. You didn't sit down one day and say I want to gain weight, but every time you take a bite of the wrong stuff or too much you choose to do that.
Nothing is easy about it, otherwise none of us would be here. I find the first thing to do to get back on track is to be accountable. Track every single bite, count calories and then it will likely be very obvious what needs to change. Unfortunately it's harder once you're out a while from the sleeve and it's more like a regular diet. I'm personally going through this now and being accountable has helped me get back to where I should be in terms of eating.
Don't give up. It's a life long battle and you haven't lost