RIO DE JANEIRO (AP) — Missy Franklin finally got in the pool at the Rio Olympics only to endure another disappointment in the most unsettling year of her career.

The usually bubbly American swimmer who emerged a darling of the 2012 London Games with five medals failed to make the 200-meter freestyle final. Franklin finished last in her semifinal heat Monday night with only the 13th-fastest time among 16 swimmers.

Her voice shaky and tears welling in her eyes, Franklin struggled to comprehend what had happened.

"Just trying to hold it together," she said.

Her time of 1 minute, 57.56 seconds was actually slower than what she swam in the preliminaries earlier in the day.

"It's so hard knowing all the work that you put in every day and then to get here and to be so far behind where you feel like you can be," she said. "But I'm not there and I gave it my best. Just disappointed that I let the team down."

Four years ago, Franklin finished fourth in the 200 free, one of seven Olympic events on her jam-packed schedule. Now, 19-year-old teammate Katie Ledecky is the U.S. freestyle star. Franklin, with a lighter schedule, is out of the spotlight, and waited three days for her first race.

Franklin just hopes she gets the chance to be part of the 4x200 free relay. She led off the relay in London, launching the U.S. to victory.

"That would mean the world to me," she said.

After her big splash in London, "Missy the Missile" chose to swim at California for two years, spurning lucrative endorsement deals to be part of a collegiate team. Last summer, Franklin moved back to Colorado to be close to her parents and reunite with her longtime club coach Todd Schmitz.

She's endured a mystifying loss of form since turning pro a year ago, struggling just to qualify for two individual events and a relay at the U.S. trials.

"That's the hardest part is I wish I could understand and I wish I could fix it," she said. "But that's kind of how my year has gone. I feel like I've worked as hard as I ever have and it just hasn't been there."

Still on her schedule in Rio is the 200 backstroke, where she is the defending champion. She failed to qualify for the 100 back at the U.S. trials and didn't defend her gold from London.

"It's incredibly frustrating," she said. "I need to keep my head up and I need to keep fighting, and that's what I'm going to do."