From what I get, Ara's trying to do what Kyung Hoon told her to do: reeducate her heart and overcome their break-up so they won't see each other suffer. After all, they've agreed to do it gradually, and by studying in the same university, it's not as if they can completely avoid seeing each other. So she probably worries about how she appears because if she shows herself as obviously suffering, she'll make him suffer, too.
Putting up a pretence of normality is the first step. Then the pretence becomes real and both will be able to move on.
What I'm more concerned about is her being honest with herself about Gyu Min. I doubt in a webtoon with so many rational people she'd do something like using him as an emotional crutch. She either needs to tell him what Kyung Hoon told the other girl, or pour her heart into learning to love him and making it work. (Yes, I believe love is something one can learn.)