Covid-19 left Nir Bitton unable to stand as it took its toll on the Celtic star.
Bitton was ruled out of Saturday's 2-0 defeat after testing positive on international duty with Israel, and he says he underestimated the virus.
The 28-year-old is no longer in isolation, but will face a series of tests before being allowed to play for Neil Lennon's side again.
Speaking about his experience in the Scottish Sun, Bitton said: “I went through some hard days with this virus. It wasn’t easy at all.
"Before I got the disease I underestimated it, but it was not pleasant.
“I had headaches, my muscles ached and I could not stand up. I had to sit.
“You do not know what you are heading towards.
“Everyone knows how the disease starts, but not how it ends.
“If it affected me, a young and athletic guy, I do not know how it affects older people.
“We see deaths and I need to say to people, watch out. Stay at home and look after your relatives. This is not an easy disease.
“I am still without taste and smell, but I hope it will come back soon and that the hardships are behind me.”
The international break also saw Celtic team-mates Odsonne Edouard and Hatem Abd Elhamed test positive, while Ryan Christie was forced to self-isolate after being deemed a close contact of Stuart Armstrong following the Southampton midfielder's positive test.
On the risk of exposure on international duty compared to Celtic's regime, Bitton said: "At Celtic we have been in a regime for four months since I returned from Israel.
“No families, no restaurants, no friends and almost no leisure life. We take care of ourselves.
“Then you go to the national team and suddenly there is a sick player.
"You find out after a few days and you know there will probably be more patients.
“There is no solution. The only solution is to cancel the squad meetings and it will not happen.
“If a team suddenly has some positives, sometimes you should not take a risk.
"You have to keep players in an environment that is comfortable and sterile.
"If that means not inviting players from a team that has had an outbreak, then that’s what it should be.”
Celtic return to action tomorrow when they face Milan in the Europa League.
