Has anyone ever had this happen?

Glow predicts I start my period on Friday I am always regular and 28 days, I go to the bathroom on Friday, wipe, and voila period blood, so I put in a tampon and move on with my life. A few hours later I take the tampon out and nothing??? So I don’t put one back in. Later that night I want to have sex so I take a bath and still nothing, have sex with my husband again still no bleeding. Entire day Saturday not one single drop of blood???? So I wake up today (Sunday) with terrible cramps, heavy uterus, and a belly ache so I go to the bathroom and some small clots but nothing on the pad so far?

Question is why did I only bleed for a minute on Friday, nothing Saturday, and now only when I use the restroom today??? I heard of periods stopping mid cycle and returning but not this.... is this a sign of PCOS or some other hormonal issue? Anyone ever has ever this happen?