Freaking out... Can I get some advice

Olly
I'm Olly... I had sex on July 7and 8 with my boyfriend. We didnt use protection .. The next couple of days haven't been feeling so well. Headache.. A pasty sour taste in my mouth. That never does away Stomach hurting. Nausea . And I've been sleeping.. But my period is two days late.. What's should I do ???