Im really confused???

Cassie • Momma of Two Graci 5-7-15 Graeson 9-7-16! Angel Momma of Two Nov 2015 and Twin B Jan 19 2016! Single Momma! TTC baby 3 via Sperm Donor! :) ❤️💜
I took an opt this morning and it was londa dark not pos yet but just took one now and it was lighter why is that