A 27-year-old married woman reports to the PMHNP that she is experiencing significant distress in her marriage because she "hates" going to social events, and her husband's job requires attending regular social gatherings. She avoids these activities because she is "terrified" she will do or say something embarrassing, and she has started pretending she has headaches to get out of going to them. Her husband doesn’t understand why she doesn’t want to go to these parties, which are typically small gatherings of less than 15 people. She admits that when she does go, they end up being "no big deal." The PMHNP will diagnose this woman with which of the following?