I had surgery on 8/30. What could be going on? My calorie intake is way down.

Had you gained it *immediately* after surgery. Could be Fluid, they absolutely fill you with saline. I've had three ops and two hospitalisations in the past two years and gained about 10 temporary pounds each time,

Or.....

Did you lose a lot on your per op diet - you know that sort of loss is Water, not true fat loss right? It's vey common to regain a bit as your body equalizes.

It sucks and is very demoralizing but ther is NO way you can gain 15lb of FAT in a week on reduced calories. It's got to be fluid.

I gained right after surgery then It all came off and quickly

water/fluid will make you gain every time.

you should not weigh after surgery (as this is what happens) and then you start freeking out over something you have no control over.

so stop weighing every day and focus on healing yourself and following your doctors orders. the first 4-6 weeks are for healing (your weight will go up and down). you will do fantastic.

I gained 7 pounds after surgery and on day five lost the whole 7 pounds