Question!

When I was pregnant two times before I miscarried, I took my pregnancy tests like 4 or 5 days before AF was due. They showed up pretty bright and you could tell it was positive. Now with those miscarriages, could that have screwed my cycle up and me not know when I actually ovulated? I mean these tests I'm taking are pretty faint but I'm wondering if it'll be after my missed period that I'll see a BFP or I'm just really not pregnant. It's confusing, is this normal? Oh I'm due tomorrow apparently according to Glow.