"It's very surreal because it's really intense. I was so committed... everybody on the show is, and all of a sudden it's over," she tells ET's Nischelle Turner. "I did really hope and think I'd be there a little longer."
But even through her disappointment, Melanie C marvels at the "outpouring of love and support and outrage" she's seen on social media, something she "really appreciates."
"I think there's a whole album out there waiting to be written after this experience," she quips of DWTS. "... I've done so much in my life. I've been so fortunate. I've had a great career. I was a Spice Girl, I was a solo artist, I've done theater, I've done so many different things, but nothing prepared me for this."
"I'm still licking my wounds. I still have a little bit of healing to do," she admits, "but there are so many positives I'm gonna take from this."
One of those positives is turning her focus back to music, something she recently did with the release of her eighth studio album, Melanie C, which is out now.
"I've spent so many years kind of figuring out who I am," she says of the inspiration for the album. "I was in my 20s when I was first working with the Spice Girls... There were little bumps along the way. I'm a mom, my daughter [Scarlet's] 12 now, and I just feel like I'm at a time in my life where I finally have found this self-acceptance."
"I was back onstage with the Spice Girls in 2019. We did these incredible stadium shows in the U.K. and I was Sporty Spice for the first time in such a long time," Melanie C continues. "It made me realize she's always in there, she never goes away; I don't become her, she's in here."
All of those experiences, she says, made her start "thinking about all these aspects of ourselves that we don't acknowledge" and inspired her to make an album "about accepting every part of myself."
"There's a few negatives to aging, most of them physical," she admits, "but then with your confidence and that self-acceptance, I think we have to hold onto those positive things."
Following the debut of her solo album, Melanie C is gearing up for the release of Spice 25, a deluxe edition of the group's debut album in honor of its 25th anniversary, which is due out Oct. 29.
"We wanted to repackage the album, remaster the album, because, of course, that's such a lovely thing to do, but we also wanted to add more," Melanie C explains of herself and her groupmates, Emma Bunton, Geri Halliwell, Mel B and Victoria Beckham. "We have these incredible fans all over the world that have never, ever gone anywhere, they continue to support us, so we dug into the archives, and we just found lots of demos, unreleased tracks."
"There's so many little quirky moments. There's a little edit of us just messing about in the studio... I think for those real fans out there who love to collect all the memorabilia, they're gonna love it," she adds. "... It brought back so many memories."
The women support and love each other "more than ever," Melanie C says, and "100 percent" want to get back on tour following their 2019 shows.
"This has to happen. We talk about it constantly. We did the shows in 2019, the plan was to continue on," she says. "Of course, the world has been in such turmoil, but the plan beyond this is to get out there when it's safe, when we can do it. What's tough is there's so many artists that want to get out there, and there's only so many venues, so we're all kind of queuing up going, 'I want to! I want to!'"
While the 2019 shows did not include Victoria, Melanie C tells ET that they're "chipping away" at getting the fashion designer back onstage.
"We would love to have her back onstage. In all honesty, I think it's gonna happen," she says. "At some point, I think Posh Spice will be back onstage."
Tune in to Thursday's episode of Entertainment Tonight for more with Melanie C.