missed period?

Christina • Life is crazy but that's what makes it beautiful.
So I started a new job and had a period like the first week and I'm on the second week of the second month and no period yet? I'm usually on time... so I took a early test at first I thought it was negative but I left it alone, and the other line is faintly there. I'm about to turn 21 and I want someone else's perspective on if I should take another or not?