My female cat’s belly is weirdly bigger and harder.

My cat will turn a year old in like around January, so she’s still pretty young. She has always been a skinny cat, but suddenly one day I noticed her belly was bigger and I thought I was feeding her too much. Turns out she has been sneaking into the cabinets and eating more of her food. Still, I think it’s very strange that her belly is so hard and bigger than before. She’s still very active, plays with my other cat and acts like nothing is wrong. She eats her entire food as well. She’s also spayed so no chance of pregnancy. What could it be? Is it me just being paranoid? Her belly looks kind of fine here, but when I pick her up it’s such a big difference!

Has anyone experienced this before? Idk if she’s bloated or sum