The actress was “pretty surprised at the backlash and drama” surrounding the film

Blake Lively was caught off guard by the negative attention she faced while rolling out her hit movie It Ends With Us.

The actress was “pretty surprised at the backlash and drama” that surrounded the romantic drama’s release last month, a source tells PEOPLE.

“She initially felt very vulnerable and upset,” adds the source. “During the promotion of the movie, not one day went by when she was not in the news in an unfavorable light. She’s just not used to this kind of drama.”

The source says the situation “felt out of control to her.” Still, Lively, 37, who next appears in A Simple Favor 2 with Anna Kendrick, “enjoys working and will continue to push forward projects that she’s excited about.”

Lively is also a producer behind the Colleen Hoover adaptation It Ends With Us, which has since become the highest-grossing box-office hit of the actress’ career so far.

Reports of tension between Lively and the film’s director and male lead Justin Baldoni caused a firestorm of media attention after the two costars did not pose for photos together on the red carpet at the premiere. They also didn’t do any press together in the lead-up to the release.

Additionally, some people online took issue with the film’s marketing campaign, claiming it was misleading for a project that deals with themes of domestic violence and trauma. And brief clips from Lively’s interviews, recent and years-old, went viral on social media with criticisms.

Lively has been open about her passion for creating the film and hoping that it sheds light on important issues and empowers other women.

“It Ends With Us is a story of the female experience. Al the highest highs, and lowest lows. And we are so proud of it,” she wrote on Instagram after opening weekend. “We have been in celebration of this film and of getting a message so important out there to the masses. Thank you all for embracing It Ends With Us with the same love, pain and joy we had sharing it with you all.”

Lively’s costar Brandon Sklenar has spoken out about “negativity” directed at the women of the cast, writing on Instagram, in part: “Vilifying the women who put so much of their heart and soul into making this film because they believe so strongly in its message seems counterproductive and detracts from what this film is about. It is, in fact, the opposite of the point.”

It Ends With Us has grossed over $300 million at the worldwide box office, though the hope for a sequel seems low. Hoover wrote a follow-up book, titled It Starts With Us, which Baldoni, 40, owns the rights to turn into a film, and he has suggested Lively direct the sequel if it happens.