Trying to get pregnant

I'd say this can happen with early testing since hormone levels are still very low, and different tests have different sensitivities. The faint line you saw could be real, or it could be an evaporation line if you checked it after the time window. Best thing is to wait a few days and test again with your first morning urine when the hormones are more concentrated, or just go straight to your PD or polyclinic for a blood test to be sure since that's the most reliable way to know.