Pattinson and Stewart as Edward and Bella
doesn't take break-ups lightly – even those on film.
"Everything in our movie, it's such a heightened version of reality," the Twilight
star, 19, tells MTV News
. "People don't just break up [in the films] – they break up and it literally kills you. It's not like you just say, 'Oh, I'm really depressed and crying.' I always had a really hard time figuring out, 'Am I doing enough? Do I look like I'm going to die?' "
Stewart, whose character Bella finds herself in a love triangle
with Jacob (played by Taylor Lautner
) and Edward (Robert Pattinson
), says she struggled when she had to film a specific scene for the sequel New Moon
"My favorite line in the book is when I have to say to [Jacob], 'It's him; it's always been him!' " says the actress. "Yeah, it killed me. It killed me."
] is very complicated," adds Lautner, 17. "There's a lot of heartbreak, there's a lot of things going on."
"Edward leaves at the beginning, [Bella] goes into this depression, I come to try and bring her out of it. Then I go through my own issues, and then she leaves me," he reveals. "It's all over the place."