Hi ! Your gain in weight may not be related to the umbilical hernia surgery
, but could just be a coincidence. You must get yourself reviewed by your GP for a possible blood sugar test, thyroid
function test. If both are normal, I would suggest you to visit an endocrinologist
. At the same time, I would also suggest you to go for some active exercises like brisk walking after getting a clearance from your physician. Wishing you an early relief of your problem.