1st frame: Iruyeh-tan minds her own business, probably walking to class or work but she obviously has something keeping her busy or preoccupied in her mind.

2nd frame: (Iruyeh-tan's internal monologue) "Ah! Anon-senpai noticed me! Our eyes locked together for a second! We must be lovers!"

3rd frame: "Oh, but of course we couldn't be lovers after all. He loves that stupid slut Heyuri-tan more than me, obviously. Ugh..."