8 Days Late

I am 8 days late today. I have a two year old and a nine month old who is still breastfeeding. I have only tracked my period since I've been married three years ago but it's always seemed pretty consistent and when I have tracked it the few periods I've had in the past three years they have been very consistent. I didn't think anything of it until I was 4 days late though. We haven't been trying because with a two year old and a nine month old I've got my hands full. But haven't been super careful either. I took a test at 4 days late and one yesterday and both were negative. But I've been feeling horribly nauseous yesterday and today. I have had terrible morning sickness with both my babies. I also had positive tests a week before my period was supposed to start with both kiddos. After the first negative I just assumed I wasn't Pregnant. But it's still not showing up and with the extreme nausea and fatigue...idk. I was definitely wanting more kids (not this soon) so being pregnant wouldn't be the worst thing. But if definitely wasn't planned.