Meghan Trainor feared her career and new romance were over after a second vocal surgery in as many years silenced her for weeks in 2016.

The pop star has just released the first single from her third album, shortly after becoming engaged to actor boyfriend Daryl Sabara and she now admits she feared she would lose everything at the height of her problems.

"I thought all my dreams were taken away from me," she tells Billboard. "Those were dark days."

She had just started dating Sabara after meeting him on a blind date set up by the couple's mutual friend Chloe Grace Moretz, and she worried that her forced silence would scare him away.

But she reveals they communicated through sign language and notes and the drama actually brought them together.

However, Meghan admits she still had grave doubts about bouncing back as a singer after cancelling a tour to undergo surgery.

"I looked at my team crying and said, 'My body was not built to be a pop star, I guess', and they were like, 'That’s not true, you were born to do this!" she recalls. "They had to really convince me - I went to a very dark place of like, 'How will I ever tour again...?

"I still get anxiety and a little scared when I see the schedule, like, 'OK, we’re going to talk that entire day and then we’re going to perform the next day?' But so far, we take it day by day and we all know we’re never letting it get back to surgery - that’s the goal."

And Trainor reveals Brit Sam Smith, who also underwent surgery to fix vocal issues, was a big help when she was looking for answers: "I was in my hotel room with bronchitis and lost my voice and had vocal cord haemorrhage," Meghan tells Billboard. (Doctors) told me, 'If you keep going, you’ll break it 'til you can’t sing forever'. I asked him (Smith), 'Do I cancel an entire tour and do this surgery?' And he immediately said, 'Absolutely, take care of your voice, don’t waste shows singing terribly knowing you’re hurting yourself. Do what’s best for those vocal cords, you just get it done and you sing for everyone again and say, 'I’ll make these shows up to you, I promise', so that’s what I did."

She has since lost touch with Sam but she hopes he has heard her post-surgery songs: "He was so kind and so nice to me, and I knew he was going through those vocal problems too because he’d been public about it... Now I have other people reaching out to me, like, 'Hey I’m struggling with my vocals' and I’m helping them out. It feels so good to be open about it and help others."