Имплантационное кровотечение на 4 день задержки? У кого так было?

I need a peace of mind.

Day 1 of my missed period I took 3 pregnancy tests. All had faint lines.

Day 4 of my missed period (today) I took a digital pregnancy test that read: PREGNANT! I’m so excited.

I have 3 kids already and never have had implantation bleeding.

Today, (day 4 missed period), I have bleeding. It’s not like my period, it’s brown and not heavy so far. But I’ve never had implantation bleeding. Can anyone ease my mind and describe to me your experience with implantation bleeding? How heavy? How long did it last? Is it possible to start on day 4 of missed period? Could this be miscarriage bleeding? All advice welcome, thank you!