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:
- 「もしかして太ったぁ?前
( より一( 回( り大( きくなった気( がするねー」- “Could it be you've gotten fatter? I feel you've grown a size bigger than before.”
Key Points
気がする marks a subjective impression
大きくなった気
( がする means Nao feels Chito has grown, not that she is proving it.
前より gives the comparison point
前
( より means “compared with before”.一
( 回( り大( きい describes being one size or one noticeable degree bigger.
もしかして frames the guess gently
もしかして太
( ったぁ? softens the direct question “did you gain weight?”