How Soon Can I Take A Pregnancy Test Inspite Of Having Late Periods?

hi I am 10 days late in my period and I am starting to wondering if I am pregnant I have taken pregnancy test and they have all came back negative. However last time I was 3 or 4 weeks late on my period and all the pregnancy test I took come back negative and it so happened I actually was pregnant. So now I am wondering if I am and how do I know for sure?