Aaron Jay, who was born on February 29, was rushed to hospital where he was diagnosed with viral meningitis and reflux.
Relieved Michelle, 34, told her Twitter followers of her joy at having her son back home – but said she is worried about the possibility of long-term effects.
The mum-of-two posted: "Our beautiful baby boy Aaron Jay Hanley is home now and we couldn't be happier.
"It has been hell. I'm not going lie and only time will tell if Aaron has been physically or mentally effected with having had viral meningitis.
"But the chances are slight so we just pray he will be one of the lucky ones."
And Michelle - who was recently named Disney's Celebrity Mum Of The Year - thanked husband Hugh Hanley for his support and gave AJ's two-year-old sister Faith a special mention too.
She added: "We certainly are to get our little man home. Faith has been the best big sister ever, nursing him every day now time for Lots of cuddles and family time.
"I love my family. More then words can say! & @hughhanley is our rock! Luv you baby xxx."
The singer had earlier admitted she was enduring the 'worst and scariest' time of her life as AJ was treated in hospital.
She posted on her Twitter page: "The last 24 hours has been the worst and scariest in my life. With Everything I've been through mentally and physically nothing, I mean nothing, compares to that of when your baby is sick.
"Our beautiful baby boy has been very looked after in hospital after being diagnosed with viral meningitis and reflux disease just to top it off. He's fighting strong & taking the antibiotics well so far. But at only 5 weeks old one can only imagine our distress as parents. "
He's very sick and in pain with the reflux. The hospital are amazing and he's well looked after. Hopefully we will be able to take our little man home soon. I'm sure we will. Xxx."