Have you had your hormone levels checked? you might have hypothyroid...or need bio-identical hormone replacement therapy?
Are you having any issues having bm's, urinating? as that could be a problem as well...are you dealing with alot of gas? have you tried simethicon if you are? if will help you pass the gas which might help with the bloat...lots of walking will help with both areas as well... this may settle down in a few more months though because it could also be that you are now becoming more active at the 4 month mark and the sutures have dissolved so your body is having to pick up the slack of this and so you may still be having swelling from the surgery...I know for me it was a good 6 months before my body calmed down. If in doubt though perhaps a call to the dr. to get some blood work so you can see what's going on.
Hysterectomy, ovary removal or not, seems to affect metabolism because many women complain of weight gain. Although sometimes the surgery seems to cause transient bloating more so than permanent weight gain. This may be due to the effect on the bowels and maybe even the bladder (and hence the kidneys) since those organs are displaced (descend in the abdomen) after the uterus is removed. And