Advice/ ideas

Af is due on 7th march and I don't know whether I'm convincing myself I have symptoms of being pregnant. 
​Have been feeling nauseous on and off for a couple of days, some smells make me feel sick! Went to eat pizza yesterday and made me feel a bit queasy. I've been having headaches everyday too! But no cramps or pains or 'obvious' signs. Wondering if anyone had any ideas? Or felt the same :)