Could it be a chemical if period came right on time? See pic x

So I read that a chemical causes a delay in period but mine started right on time.

I tested with clear blue early 5,4 and 3 days before my period, no obvious line until I squinted and took a picture convinced I was pregnant just super early and then tested with first morning urine two days later expecting there to be my rainbow BUT NOTHING

So I'm wondering was it just the clear blue test playing tricks cos I know that they can do that :/ or was it a chemical

Just want all my facts together before I go to the doctors