Deceiving eyes

Took a blue dye hcg test. Thought I saw a line somewhat. Tried to take pictures and zoom in. Nothing. AF is due in two days. Believe the line I supposedly saw was just my eyes wanting to see something. Why is baby #2 so much harder. If AF doesn't arrive by te weekend I'm taking an actual digital test with the husband. I'm starting to feel discouraged but then baby fever kicks up real bad, that's the only thing keeping me from giving up.