A nurse says the effects of "long Covid" mean she is "not the same person any more".
Lynne Wakefield from Holyhead is still suffering with fatigue and "brain fog" after contracting Covid in June 2020. She said her employer had been "very good" supporting her, but other NHS staff told BBC Wales they felt pressurised to go back to work.
The NHS Confederation said there was a package of support for staff affected by "longer term effects of Covid".
A recent survey suggested about 56,000 people in Wales have symptoms of long Covid, which include fatigue, headaches and coughing.
Other NHS workers with long Covid symptoms, who did not want to be named, told BBC Wales Live how they feel about the ways they are being treated by their employers:
"I knew that returning to work would put my recovery at risk, but it was work or starve. On my return, I was informed that any further days absent in the next 12 months would result in a formal warning."
"I'm so worried about losing my job as I've been off work for so long and I'm still nowhere near well enough to return."
"If they say I have to come back or be dismissed, I'll have to do it, I'll have to try [and go back] and survive. I am so emotional at the moment, I can't stop crying - I feel I am going crazy."
Source: BBC News, 28 April 2021