Clear blue

Mommies n mommies to be please help me clear this out... my clear blue says I'm pregnant 3+ which on the test means I'm 5 weeks, but counting by my period n due date calculator that's inaccurate cause it says 4 weeks n a few days pregnant.

My period was on the 27th of sep for 4 days, n my period tracker said my next expected period would be on the 23rd of Oct bt it didnt show cause I was pregnant.

Since clear blue says its 99% accurate, can it be wrong? I'm confused.