My period is late. Idk why though?

So I'm a 15 and a virgin so even though my period is late I don't have to worry about being pregnant lol. I'm also sick right now. I got sick Friday night. So I'll have my period and be sick at the same time which has never happened to me. So that should be an experience lol. I'm a day late but idk why and it kind of sucks cause now I don't know when I'll get my period. Usually I'm irregular but never late. Idk if it's normal or if it means something is wrong. Please comment if u know some reasons as to why my period is late even though I've never had sex. Also please comment any tips or advice or your own experiences for being sick and being on your period at the same time. Thanks :)