Lindsay Lohan cried when she saw her little boy watching one of her old films. The ‘Mean Girls’ actress, 37, had her first child Luai with husband Bader Shammas, also 37, in July, and has said she got emotional when he watched her in ‘The Parent Trap’ as she didn’t think he knew it was her on screen. She told ‘The Drew Barrymore Show’: “Oh actually, I just wrapped a movie four days ago and I came home from work and my son was getting ready for dinner time. “And I opened the door and he was watching ‘The Parent Trap’. It was just on the TV. “And I started crying because I’m like, he doesn’t eve…