It was supposed to be a vacation they'd never forget. Two friends from Dallas were shopping in Barcelona's bustling La Rambla tourist district Thursday when they realized something was horribly wrong.

"Sheer terror," said Valerie Istre, a mother of three. "I've never seen anything like it with a mass group of people, just trying to get away and not knowing where to go, or something else was going to happen."

Through a twist of fate, just moments before a van plowed through a crowd, Istre and her friend stepped into a store to replace her friend's sunglasses.

"We had just been there," said Istre. "If my girlfriend hadn't dropped her sunglasses, it would have been us."

They hid inside for three terrifying hours, not yet knowing what had happened or if they were safe.

"The lights were off, the music was off," said Istre. "We didn't know if people had guns, if there were terrorists coming in with guns."

That's why Istre sent her daughter a picture of herself, snapped minutes earlier, along with a text -- "I love you so so so much," she wrote, in case she didn't make it out alive.

"My daughter is almost 12 and I didn't want her to know anything was wrong but I wanted her to know that I loved her," said Istre, holding back tears.

When Istre was finally able to go back outside, she took cell phone video of the eerie scene, showing police and crime tape.

"It's a very sweet, community-oriented place. You can just tell they're heartbroken," she said of the mood in Barcelona one day later.

"I'm just so sad for all the people that were there, and affected and their families," she said. "I'm a firm believer in God and I think if it was my time yesterday I would have been okay with that."