My peroid was 3 days late and then I started I taken a tes it said I was not pregnant so when should I take a nother one

When you have missed a period by a week,then you take a test with first morning urine.
Being late does not mean you are pregnant,it just means you were late.It happens a lot!

You have your period so you are not pregnant now.

You can always take a blood test. They can detect pregnancy from 7-12 days of possible conception.

Good luck,

Sarah