Implantation bleeding?

So... I was hoping I was pregnant... yesterday I felt terrible! Extremely tired, just felt yuck. I had a headache and just felt queasy. Well later on that evening, I started bleeding so I thought well dang, I just started my period.. early.... Later on when I went to change my tampon there was hardly any blood at all. So I didn't put in another. I haven't bled any more until now. At 4:09 pm the next day... could this be implantation bleeding? Has this happened to anyone else?