Natural is:
On Saturday, Luna visited my house and asked me how my work was. I told her that it was fine, but, truth be told, I’d lost my job and been unemployed for 5 months. I didn’t want to upset her.
In the US, the expression is ‘keep something under wraps’ (not ‘wrap’). It doesn’t really apply here because it suggests temporarily withholding information. It’s unnecessary and therefore unnatural.