old before my time has given you excellent guidance! I would suggest if it continues perhaps having your thyroid checked as well...but it is still most likely just getting back on track from the surgery! Try not to fret just yet!
Welcome to the community.
You are still early post-op so this may just be due to the lack of exercise early post-op and your body trying to heal. However, studies do show an association between hysterectomy and weight gain. This seems to be more prevalent in women who were prone to weight gain prior to hysterectomy.
I have always been thin and could eat anything I wanted and not gain an ounce but since my hysterectomy, I eat quite a bit less (thankfully I lost my appetite post-surgery!) and am able to maintain a normal weight.
Hopefully, once you get back into your normal routine, you will be able to maintain a normal and healthy weight!