Y'know, this is actually a significant departure for Morinaga Milk.  I mean, her characters have had anxieties, but only along the lines of "She's so awesome and I'm not (plus I'm a girl), so any hints I might be thinking I see of her maybe liking me must be wrong" kind of stuff.  So self-deprecating, even a bit insecure, but nothing serious.
What we have here on the other hand, seems to be operating at an existential level--"Am I anything if she isn't looking at me?  Is there a point to my existence?"  This is not a kind of thinking Morinaga Milk characters have ever done before as far as I can remember.  Living for the romantic partner, and maybe being supported by them to do . . . something, has always been more than sufficient for girls in Morinaga Milk stories.  Often taking care of the partner has even been the basis of a character's career, going right back to Girl Friends--Mari became a nutritionist basically as an extension of cooking for her beloved Akko, and that was totally enough to make her happy and fulfilled.  So yeah, this one is different.