Faint line on Pregnancy test?

My cycle usually only lasts 28 days, last month it was 2 days late and i only had a period for 2 days. I bought the 7 dollar Preg test from the dollar store and took it today, the control line was there, but the test line was Very very faint. So i went to wal-mart and got the equate brand and i checked it 2 minutes later like i was supposed to and there was a VERY VERY faint line in the test area. I thought i will give it a few more minutes and when I went back there was no test line! HEEELP!