chemical ?

hello ladys! last month around the 19th i did a pregnancy test and got a positive which is the first test you see on the picture the next day a tested again i got a negative i waited a day and got the first response test and got a vfl the next day i did another test to see if it got darker and i got a negative and i started my period that day it was 3 days late and very light compared to other months... was this a chemical pregnancy? How do i know?