Late and spotting. Please help!

So yesterday morning I was spotting. Very dark. Which happens when I start my period. Then within hours I'm heavy bleeding, so I put in a tampon, checked it later in the day, and it was still just a dark spotting. About 1/8 of the tampon had dark blood on it. So I didn't have anything in all night, went to wipe this morning. Nothing. Went to the bathroom just now. Nothing. I don't want to get my hopes up. Anyone experience this?