Some help! give me some advice?

okay so i got my first job. I've worked there for 6 days already..doing okay & i work at hooters btw. I'm a hostess there. BUT last time i worked my boss realized i have been giving the wrong receipts out(when i work retail of course) so he checked me down for that. I've been throwing up all night and i dont think i can work tomorrow. & tomorrow theres a big USC fight & its gunna be crazy busy..& i should be there. i reaaally dont want to get fired! but if i call in sick (my mom even said she'd do it so i'd seem more believable) (im 17 btw) do you think id get fired if i call in sick?