Period is a Day Late & Negative Pregnancy Test

Jade
Okay! So I was due for my period yesterday! Never showed up. Nothing today. My period comes like clock work. I know when it comes every month and I have never had an issue with irregular periods. I even put tampons in my purse three days ago because if I didn't conceive I knew it was coming. I'm not showing any signs of my period either. Usually a day or two before I get really really light bleeding when I wipe and I know my period is coming. Well that has yet to happen. Everything is upsetting my stomach and I've thrown twice in the last week. 
Opinions Please!!! I'm going crazy not know if I conceived or if somehow my period is off...