The TV star, 52, announced in 2020 that she was leaving the ITV programme after re-assessing her life amid the COVID pandemic.
McLean had been working on her mindset company This Girl Is On Fire, which aims to help women think differently about themselves, and had enough corporate work lined up to ensure the money kept coming in.
She said when she was dropped by the brands “financially, it was a punch in the stomach”.
Opening up on the Secure The Insecure podcast, she said: “On the day that I announced that I was leaving, every brand dropped me, every single one.
"I went from, ‘OK I know I have this amount of money coming in and this much work that will see me through to the next six to eight months’, gone. Literally overnight it disappeared.
“That’s how big a deal it is walking away from TV.
"For me, financially it was a punch in the stomach, because my safety net was gone. I can’t turn back and I can't change my mind because I still want to do this thing."
McLean said the brands that dropped her when she wasn't a big TV star, which she didn’t name, were all about raising women up and making them feel good.
“But actually they didn’t care about that, they only cared about my profile,” she added.
Mum-of-two McLean was on Loose Women for 13 years.
She recently told the Mirror she had “no regrets” about moving on from the ITV show.
Watch: Sir Rod Stewart demands to be called 'Sir' by Andrea McLean on Loose Women