please help!

Heather
I took a pregnancy test last Friday and it was a digital. It said No- so I put it in my purse to throw it away. I forgot about it. I got my what I think is my period yesterday morning. This morning I saw that I still had the test in my purse so I grabbed it to throw it away. I looked at it and it said Yes+. How can that be?! I am so confused right now!!! Someone please help?