M.F.
With my first I tested positive on 2 home test and then went to a clinic and got a negative. I had a blood test and it was positive. I was one week late. With my third I was a few days late with my period and I went to the dr and the test was neg. I went back a week later and it was postive. Wait a week and if you still don't start then take another and if still neg call doc.