How do you tell if it’s an indent line or a second line on a pregnancy strip??

Lisa • Happily married to the man of my dreams 17.08.2019!!! Baby boy due 21/10/2020 💙💙

Yesterday when I tested I’m sure it was a second line. I posted the picture on here and some people said it was a second line but it could also be an indent, well I’ve tested 3 times today and I s ire there’s a line but it’s still very faint so it’s barely visible, is it possible that they’re all indents? I’m really not sure