8 days late

I’m 8 days late. And I’ve taken 3 at home pregnancy tests - all negative. But I’ve been feeling extra nauseous and having horrible headaches lately. I usually PMS really bad a week before my period and this month I didn’t, nor last month. My period is usually super heavy and last month I barely even needed Panty liners. I feel like I’m getting too excited but because the tests have come out negative, I just don’t know what to think! My period is never late. I’ve been maybe a day or 2 late when very very very stressed but things are going so good in my life right now, I don’t feel anything but the regular stresses of daily life. What do you all think???