The presenter - who travelled 500 miles from Edinburgh to London in a week, much of it on a bike - said she felt like she had been "traumatised" by parts of her ordeal.
McCall, 46, confessed she was in such pain from her punishing days in the saddle that she was unable to celebrate Valentine's Day when she was finally reunited with her husband Matthew Robertson.
People who followed her progress during the seven-day challenge saw her regularly in tears, including a notable appearance live on BBC Breakfast when she looked like a broken woman ahead of a swim across Lake Windermere.
Reliving her experiences during an interview for ITV's Jonathan Ross Show, she said: "What's quite weird is that since I've had children I've sort of stopped crying. I put a lid on it quite a lot because I don't want to upset them or worry them or anything.
"And this journey, this week I went on, was the toughest thing I've ever done. I've never cried so much. But actually I look back on it and it wasn't a bad thing. I was so exhausted, so physically and mentally drained, that I didn't have the normal barriers I would have to stop myself.
"So if I needed to cry or something had upset me, I just cried. It was kind of amazing. People keep going, 'was it the worst thing you've ever done?'. It was the worst and the best all rolled into one."
The first day of her challenge saw her cycling for 17 hours. "I felt like I'd been traumatised. I couldn't sleep because I kept getting mental pictures of what had happened during the day," she told Ross.
The pain from sitting in the saddle had to be numbed with anaesthetic which she mixed with chamois cream to make it more bearable.
But she said she was in no mood for passion when she finally arrived in London on February 14.
"I'm afraid we had to rain check Valentine's Day. It was like, 'No, I'm sorry'," McCall said.