Feeling you've gained weight with 〜気がする

Grammar Explanation: Thinking or feeling something with 〜気がする

Nao sees Makoto’s cat, Chito. She stops to pet the cat when she notices something.

なお:: 「もしかして太(ふと)った？前(まえ)より一(ひと)回(まわ)り大(おお)きくなった気(き)がするねー」; "Could it be you've gotten fatter? I feel you've grown a size bigger than before."