The England forward Fran Kirby has spoken of how close she came to telling Phil Neville, the England manager, and her manager at Chelsea, Emma Hayes, that she was quitting football as she struggled to recover from a debilitating illness that left her “struggling to feel human”.

Kirby told Alex Scott’s isolation Instagram Live series Scottie Talks: “That’s changed in the last few weeks, obviously, because I’m feeling better. But I’ve probably nearly called Emma Hayes and Phil Neville so many times to say: ‘I’m done.’”

Kirby, who fell ill with pericarditis after Chelsea played Manchester United at Kingsmeadow on 17 November with “really bad chest pains”, has not played since she was diagnosed with the condition, which is caused by fluid in and inflammation of the sac that protects the heart.

“It was a bit scary, I went a bit lightheaded, a bit all over the place, a bit disoriented and was stressful because the chest pain wasn’t like heartburn or anything, it was really intense,” Kirby said.

“I think I’ve dealt with the illness really, really well but I did get to a stage where I was thinking: ‘I don’t know what it is like to feel normal. I don’t know how it is to wake up in the morning and feel like a human being and not feel like I’m struggling to walk down my stairs, or I walk down and have to sit down halfway.’”

Chelsea’s Fran Kirby last game was against Manchester United in November. Photograph: Dave Shopland/BPI/Shutterstock

The striker is still recovering from the illness but conceded she is having to carefully manage her recovery. “I’m still having some symptoms here and there but it’s better than what I was,” she said. “I’m trying to take it day by day.

“Everything I do has to be symptom-free before I can do anything. It’s not like an injury where if you feel it a bit you just carry on and it goes away.”

The former Reading forward had kept the extent of her illness concealed until February when Chelsea published an interview where she spoke of being diagnosed with pericarditis. She was unable even to become frustrated by the speculation over her health, form and fitness because she “just felt so poorly”.

“I was in a place where I just completely zoned out of everything. I was a ghost, a zombie, I wasn’t really there. I went from pushing myself to being able to train all week after coming back from injury and getting back involved to not being allowed to walk up the stairs more than twice in a day,” Kirby told Scott. “That’s how extreme it was. I wasn’t allowed to go for a walk, I wasn’t allowed to do anything that would put stress on me, I had to lay on the sofa. For two months.”

Now, though, there is light at the end of the tunnel. “I’m in a good space and hopefully I keep getting better and better and am able to do more exercise, which will help.”