Chwalinska, ranked 113th in the world coming into Roland Garros, had to battle her way through three qualifying rounds in Paris and dropped one set in her eight-match run to the last four which culminated in Wednesday's 7-6(3) 6-3 win over Russia's Anna Kalinskaya.
In 2021, Chwalinska announced she had been suffering with depression for over 18 months and was stepping away from the court.
"I pushed at the beginning. I thought that I just need to stay very strong, tough, and just keep practicing," Chwalinska told reporters after Wednesday's win.
"But then I just couldn't get out of bed anymore. I was just lifeless, to be honest. I knew that I need to take a break, because otherwise I'm just not able to live.
"I honestly didn't know if I'm gonna come back or not. After, like, months, I decided to come back. I needed to figure out a few things in my head, I would say. And I came back. I'm happy that I did."
Chwalinska had previously never gone past the second round at a Grand Slam, and was asked what she was doing to cope with finding herself in uncharted waters.
"I'm not into social media, I would say, I feel like it would be too much for me at this moment," she said.
"So that's one of the things that I'm doing now is just I post, and then I quit.
"Other than that, I have great people around me, that are with me for many, many, many years. So I can trust them and tell them anything that I feel."
Chwalinska's junior career was played alongside compatriot Iga Swiatek. The pair led Poland to victory in the European Under-14 Girls' Team Championships in 2015, and as doubles partners they were European Junior champions.
They reached the Australian Open girl's doubles final in 2017, but since then they have taken very different paths with Swiatek winning six Grand Slams, including four French Open titles.
While Swiatek went out in the fourth round this year, Chwalinska has already earned more in the last few weeks in Paris than in her entire career, but the time to bask in her achievements will come later.
"I feel like I just, for some reason, don't process it," she said.
"I'm just focusing on every single match. I honestly don't feel like it's a huge, huge moment for me. But definitely after the tournament finishes, I will have time to be grateful for what happened and process it as well."
Chwalinska will face another Russian in the semi-final, after 25th seed Diana Shnaider stunned world number one Aryna Sabalenka in Wednesday's other quarter-final.
