Health Secretary Matt Hancock said coronavirus had left him feeling as if he had swallowed razors as his body fought against the virus.
Mr Hancock said he was unable to eat, drink or sleep properly for "two days or so" owing to the impact Covid-19 had on him.
Describing his own experience as "pretty nasty", he told Good Morning Britain: "I had two days or so when it was like just razors in your throat, a very, very sore throat. I couldn't eat and I couldn't drink.
"The worst bit was on the way down, worrying how bad it would get because we've all seen how bad it can get and it seems to be indiscriminate."
He said he had also suffered a "bit of a cough" and lost half a stone in weight.
The Health Secretary tested positive for Covid-19 last week just hours after Boris Johnson announced he too had contracted the virus.
Mr Hancock came out of self-isolation yesterday but the prime minister is thought to still be self-isolating as he is still suffering from mild symptoms.
- ITV News Science Editor Tom Clarke reports on Covid-19 testing in the UK
The Government has been criticised for not carrying out enough coronavirus testing, but Mr Hancock said he was committed to increasing testing capacity to 250,000 a day.
Currently, the number of tests being carried out each day in the UK is around 10,000.
Matt Hancock told ITV News Science Editor Tom Clarke it was "unfair" to say there had been a shift in opinion as to whether testing was critical to the UK's response to the coronavirus.
"I think that's a bit unfair on the team who have been ramping up to 10,000 tests a day. I set them that goal and they met it, to get to 10,000 by the end of March.
"After all, just a month ago, we had just under 2,000 tests a day and we were one of the first countries in the world to develop a test at all.
"And now we have the new goal, both for my team and the whole life sciences sector, to get to 100,000 tests a day by the end of the month."
It comes as the John Hopkins University in the US, which is tracking the global picture, said Covid-19 cases have now passed one million across the world.
Elsewhere, the NHS Nightingale Hospital at the ExCel centre in east London has been officially opened, while two other temporary hospitals have also been announced for Bristol and Harrogate.
Speaking on BBC Radio 4's Today programme, Mr Hancock said it is unclear whether he is now immune to Covid-19.
"I took advice on that and the advice is it's highly likely that I am now immune, or have a very high level of immunity," he said.
"But it's not certain."
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