I have gotten faint lines on 2 test. I’ve gotten many faint lines before how do I know if it’s the start of something real?

Yesterday dollar store had nothing on it but next day faint line.

The blue test had a faint line on it within 3mins and this is a photo maybe 30 min later when it’s “darkened”. I’m confused I have one test left. when would I start having darker lines if I where pregnant?

I could be wrong and not have any lines at all I’m unsure!