"An Unfortunate Slight"
Here's a fun test of your self-respect: A certain party whom you are admittedly "sweet on" discusses plans for an activity the following night with someone standing nearby you, but never invites you outright. You overhear vague details of "when" and clear details of "where" (interrupting to ask, "oh, really, where's that located?"). You ask another of the group (who was invited outright, but cannot attend), and he is "pretty sure" that it is not an exclusive event, but you can't/won't call any of the presumed involved parties to ask as much. And as of this afternoon, you have received no similar invitation via phone message, as the other had.
Do you arrive at the location, hanging around indefinitely until the parties arrive, and risk the awkwardness of being the unwanted fourth in the group? Do you show up, and use the painfully transparent "what a coincidence!" approach? Or do you go home, telling yourself that if you weren't invited outright, the afore-mentioned "certain party" must not be desperate for you to be there--thereby risking the loss of a possibly great evening of conversation and companionship?
While you are deciding, you wonder why the certain party didn't invite you, in person or by phone.
It's not that she thinks you unworthy.
She may just need a moment to deliberate.