Is it normal to have gain 5lbs in a week after gastric sleeve ?

A 5-pound gain in a week can feel concerning, but it doesn’t necessarily mean fat gain. At almost four months post-op, your body is still adjusting, and fluctuations can happen. Water retention is a common reason, especially if you've eaten more salty foods, had hormonal changes, or increased exercise intensity. Constipation can also contribute, as slower digestion can lead to temporary weight increases.
If you've had more carbs than usual, your body may be storing extra glycogen, which holds onto water. Normal weight fluctuations are expected, and even changes in the time of day you weigh yourself or the scale you use can make a difference.
If your habits haven't drastically changed and the gain continues for another week or two, it may be helpful to track your food and fluid intake to see if anything stands out. However, if this is a sudden spike and nothing else has changed, it’s likely temporary.

Hello, I hope you are well. There are plenty of factors that influence weight gain, specially when its so fast. Hormonal changes usually have an importat role to play. It would also be good to review your eating patterns, possible anxiety, and level of activity over the past few weeks.

It is normal for you to go through stalls and even a little up and down after surgery.  If it lasts more then 3 weeks, the nutritionist at your surgeons office will want to see your food log and review where adjustments can be made.  

Most of my patients hit a period of time when they are not losing weight and hit a "stall" or "plateau". Especially in the 3 to 6 week period after surgery. It is common as your body adjusts to it's new stomach.