Was this a chemical?

So my period was several days late.. on the 3rd day past expected start day, I took an FRER test. Waited the 5 min window and didn’t see anything so put it in a drawer out of frustration. 4th day, I started getting red discharge, then the 5th day, full flow/aka cycle day 1 of a new cycle.

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I did some cleaning and came across the FRER test (picture)

and see the faint line. Now it has me wondering if I just had an early MC/chemical loss? Thoughts?