You made my eyes fill with tears ... "I always forget the time difference" I can not say why, but my interpretation says that it's been well over a year and that probably the protagonist was remembering the call.
maybe i'm a little sad
... oh no that makes it even sadder D: I'm glad people are finding that there are multiple ways to read it though, I tried to make it quite open-ended and open to interpretation... thank you so much for your comment <3