Period is a week late😟

So I had my first baby in October 2017 naturally (dunno if that makes a difference with hormones or whatever) I’ve had 2 periods since then but this one is currently 6 days late. I’ve taken several at home tests around the first and fourth day of my missed period and also had bloods drawn on Tuesday that came back negative. Although I’m nauseous every day for the past week and a half, have had diarrhoea, increased appetite and my nipples especially while breastfeeding have all of a sudden become sensitive again.. is it possible the blood test was done too early? With my first I found out before I’d even missed my period😂 I can’t think of any other reason it would be late