Adele was so worried about living up to the success of 21 that she nearly quit music for good.
Her Grammy and Brit Award-winning album has sold more than 30 million copies worldwide since it came out in 2011.
Speaking to Graham Norton for upcoming programme Adele At The BBC, she said: "I just got really worried that I was never going to make anything that anyone liked again. It was just being self-critical of myself, it was nothing else other than that.
"And also I started to wonder, maybe 21 being so successful is enough for everyone? But I realised it wasn't enough for me. So, sorry, I'll make your ears bleed again."
The 27-year-old made her comeback in October with chart-topping single Hello, while her third album, 25, will be released on Friday.
After Norton asked her whether she was more "guarded" and "self-protective" with the new album, she said: "Yeah I was, just because last time no one was waiting to try and work out what my songs meant.
"I was so open about what the songs were about before, and I hurt people's feelings with that, a little bit. Being so honest, and being a bit more immature then than I am now, I was like, 'I don't care, like, he broke my heart, whatever', and stuff like that. So I felt quite bad about that."
Adele, who has a three-year-old son Angelo with her partner Simon Konecki, added: "I have a lot of different things going on now. I have a family that I love, and I'm a lioness, and I want to protect them, and stuff like that. So I'd also like people to interpret these songs how they want to, rather than me shoving it down their throats."
In the programme, to be screened on Friday at 8.30pm on BBC One, she performs music from across her career - including classics Rumour Has It, Someone Like You and Skyfall. From her new album, she performs Hello, When We Were Young, and not-yet-released song Million Years Ago.
She also spoke about how her voice has changed after her 2011 surgery to treat a sore on her vocal cords, telling Norton: "At the very beginning it changed, it was very clean. Obviously I used to smoke quite a lot, so all the scars that my voice had from most of my life were gone, it was like a brand new voice.
"I can sing a lot higher than I used to, and also a lot lower than I used to ... and now someone's going to challenge me and I won't be able to do it!
"And also in pregnancy my voice got a lot lower, which is why Skyfall is so low. I couldn't get up there for Skyfall."
Adele said she had not decided whether to tour the new album, adding: "I want to make sure if I do it I can do it," but confirmed she would perform shows in England.