If you stay up past when the server ticks over, it will not pop up the next time you log in. You gotta be proactive about it. Not sure why it won't pop up just because you stayed past the time where the server changes into the next day, but that's that.

Ticks me off because I missed one day and now I can't make it up :/

It won't pop up if you were online when the server shifts over to the next day. I'm not sure if it has to do with interference of your computer's time set being different from server time because there is a point where it's "the next day" but you can't claim it yet.

*... that really *s. Sorry I misunderstood you.