a 5-6 lb gain in two weeks is almost too much to be due to a decrease in exercise or increase in food - so I suspect at last some of that is either water or full intestines. If so, at least a couple of lbs of that should drop off within a couple of days. As for the rest - if you're no longer logging your food intake, I'd start with that to see what and how much you're taking in. I find that if I take in more than 1700 calories for more than a day or two, my weight starts heading up (and that number is going to be different for everyone depending on age, gender, activity level, etc...). I'm OK with calorie counting, but some people hate doing that. If you're one who doesn't like it, then I'd go back to eating like you were a few months after surgery (as in NOT all the way back to protein shakes and an obscenely low number of calories - but the whole spiel of eating protein first, then nonstarchy vegetables. And then, if you're still hungry, maybe a small serving of fruit or whole-grain carb).
losing weight can be a huge struggle once you're a few years out, but people do it...