Pregnant ?

Ive been worried because I came back from traveling and I ate on the streets the whole time and ever since last Thursday my stomach has been hurting, throwing up, bloating… etc i had my period December 28th -Dec 31st. I had sex during my period and 3 days of the first week of January. Do you guys think this is pregnancy symptoms? Or symptoms from maybe a stomach bug? Because I got my period in December so that means I didn’t conceive then right? I’ve been cramping this whole week supposedly I’m ovulating this week. What do you guys think it is? Is there a chance I’m pregnant? Or no since I had my period December. Can you only get pregnant during ovulation?