A satire of misogyny
This movie is disguised as a comedy but it's really an allegory for how women are treated by men in society. She's trying to navigate a male-dominated world while getting persecuted for her sexuality at every turn. The running gag of the movie is that people mistake Meghan for a whore: this is how women are often labeled for expressing themselves sexually. However, her fiancee had left her for another woman, which is pointing out the hypocrisy.
Another significant theme in the movie is that men are only willing to help Meghan if she offers up sexually-motivated favors. The cab driver, the Jewish guy, the nerdy kid. Once again, this exposes the double standard imposed by men, because they are ones who have boxed her into the "whore" role in the first place.
It's the plight of many modern women: Meghan is just trying to establish herself as an independent career women, yet she's constantly being judged and objectified. A single promiscuous act and she's forced to run the gauntlet.
It's funny because I bet a lot of people think this movie IS misogynistic, but it's actually one big tongue-in-cheek critique. It's almost a work of feminism.