Evap lines?

So I’ve been testing everyday for the past 10 days. All negatives and no evap lines. But the last two days I’ve tested have looked negative but when I look at them later there are super super faint lines on them. But none of the rest have evap lines. All from the same box. Could I be getting a positive but there is not enough hcg present yet that it’s showing later? I’ve never had evap lines before and none of my past tests have given me any. What should I think? Positive or negative?