possible pregnancy

Tavie
I started my period early, if you can even call it a period, it was a medium flow and lasted 2 days and then has stoped since. My period has always been normal and last 5 days or so. I have been having a little bit of nausea and stomach problems with certain foods I eat.  I have read a lot about implantation bleeding and it usually is light colored but I didn't know if a medium 2 day period could actually be implantation bleeding. Any takers on if they think I'm prego  before I go buy a test? And also i could only be 3 weeks prego if I am  so is it possible for these things to be happening to me?