28 days late

Well I’m now running on 28 days late... doctors appt tomorrow and about to be late for my next period. No sight of period to come.... taking tests and 1 was faint Awhile ago but the rest have been negative. Can twins cause this to happen. They both run in my SO and my family... either way hopefully I get some answers tomorrow. With my first I didn’t know I was pregnant till 12weeks and that was bc I needed my gall bladder removed. Had no morning sickness, still had light bleeding everything so this is interesting.