Mother instinct?

Hi.
I wrote a while ago saying that I had my Chachi spayed on July 31. Almost 1month.
Before she got the surgery, she very loving with her 3 young kittens. She'd snuggle with them.
Now since the operation, she has become very aggresive with the little ones.
She goes on and hisses or growls at them. She doesn't want them near her.
Is this normal when they are spayed.
Thanks.
Angie

Her tummy is probably sore from the operation and the kittens are probably trying to suckle from her.

I'll keep an eye on them!
Angie