The former TOWIE star has now urged people to stick to the Government's rules after a number of his family members got Covid-19 despite not mixing.
The reality hunk explained that his father – Mark Snr, 64 – felt bloated and as if he had grit in his eye, as well as having no appetite and fatigue.
He was then taken to hospital as his oxygen levels were too low, which left Mark seriously concerned.
The 33-year-old wrote in The Sun: "It's at moments like that you think, 'I may never see my dad again.' All you can do is hope for the best."
In recent weeks, two of Mark's uncles, his grandma, grandad and mum, as well as Mark Snr, have all battled coronavirus.
Mark said: "The frightening thing is that no one in my family has mixed at all.
"No one saw each other over Christmas and they haven't been socialising."
His footballer brother Josh is still feeling the after-effects of the virus too, five months after he had it.
Mark revealed that Josh still can't smell or taste.
The Essex lad, married to Michelle Keegan, has now urged people to stick to the rules and "behave" – especially those having parties in lockdown.
"We've all broken rules in our lives," he added, "but when it comes to a virus that's killing people, now's not the time."
He is hopeful that the vaccines are the "light at the end of the tunnel" and will help us "get back to normality".
But he warned: "Until that day, stick in there, obey the rules and stay safe."