Stop it. Just stop. Get off -- or on -- the meds. Whichever one it is, do the opposite. Fire your agent. Remove yourself from under Vince Vaughn. You need help. Look at your last five movies, all made in the last three years: The Break-Up (in which you are an accessory of Vaughn's), Rumor Has It (in which you were an accessory of Kevin Costner's), Derailed (in which you were an accessory of Clive Owen's), Along Came Polly (in which you were an accessory of Ben Stiller's), Bruce Almighty (in which you were an accessory of Jim Carrey's). I sense a pattern. You have created your own niche market -- the sidekick chick who looks and acts smartly but is really just window dressing. These are bad parts in worse movies. You can do better.
Remember when you did Office Space in 1999 -- how adorable and engaging you were? That's because you had writers who wrote a character that uses your talents and a director who plugged you into the movie as a whole. Remember when you did The Good Girl in 2002? I was, and am, incredibly impressed with your acting ability. The Good Girl was a triumph, one of the best movies (and performances) of the millennium. The way you're going, it was the role of your career. Treasure it.
Even though it was ultimately a letdown, Friends with Money has been your sole step in the right direction in the past three years. Keep working with people like Nicole Holofcener, but stop doing these other flim-flam projects. You don't need the money. You don't need the exposure. All you need do is make sure your talents are being served. Make a film only when it's right, and you'll be more than just a Friend. You'll be a movie star.
P.S. The New York Times, not to be outdone by me, also has your welfare on its mind.