I'm 18 and had unprotected sex almost a month ago on the 24th. I wasn't expecting my period until the 10th of this month. The couple weeks leading up to it I'd get a slight tingly light headed feeling sometimes around noonish after eating. I also have been feeling more tired and been making bathroom trips a bit more than normal. On the 7th (four days before my period) I went to a banquet and spent a couple hours dancing there. When I got home I discovered I had started my period. So the next morning I went and took a pregnancy test, it was negative. My period lasted for about five or six days and was enough that I could wear a pad all day, but wasn't as heavy as it normally is. In that same week I had a stool that was loose and more of a deep greenish color. I know if a color change persists in your stool for more than a week to see a doctor but it was only that one stool that had a color change. I'm wondering if I tested too early, shoould I go and buy another pregnancy test?

If you got your period you don't need to get another test. You most likely aren't pregnant. Wait to see what happens next month.