Can I test?? Bfp?!

Kelly • I have two beautiful children paisley grace and Joshua Christopher and an amazing husband of 6 years they are my world!

So I am currently 7 days late and tested on Sunday and got bfn, when should I test again cause I have never been this late and never missed a period except when I was prego with first child. Opinions please tired of getting discouraged with bfn and wasting money on test? But my body as been out of wack in a lot ways lately and if I'm this late idk what else this could be so what should I do??