Pregnancy & Periods

I'm slightly freaking out. My bf and I were not and are not ttc but we're both worried that I might be pregnant. We had sex a day or two after my last ovulation day & my period was suppose to start 3 days later. My period ended up coming 8 days late which its never has come that late it's either 1-3 days early or 1-3 days late always has been. I didn't pay that any mind but then I started not to feel well like 2 weeks after my period. Since then I've had nausea almost every day. For almost a week I couldn't keep anything day without throwing it up. I've experienced heartburn for the first time in my life. I've had backaches and have had some cramping that's been different from period cramping. I have a doctors appointment in 2 days, but I'm still super nervous.