United Kingdom, Aug. 13 -- Jessie J's hair was falling out "like crazy" after she underwent surgery.

The 37-year-old pop star underwent a mastectomy in June, after being diagnosed with breast cancer, and in a video filmed two weeks ago, Jessie revealed the physical toll of her surgery.

In a video posted on Instagram, and filmed before a TV show appearance, Jessie explains: "My hair has been falling out like crazy since the surgery.

"Five weeks today since my surgery and I'm feeling okay."

Jessie admitted that she doesn't know what the future holds and that her health troubles had changed her "perspective on everything".

The singer - who has son Sky, two, with Chanan Colman - said: "I'm just trying to figure out what the next six mont...