False positive?

Macy

So I took a test last night and it was negative but I looked at it this morning and it was positive. Do you think I didn’t wait long enough to look at it last night or is that just the evaporation line that makes it look positive? It wasn’t a faint line though it was very dark. I didn’t take a photo of it because I was in a hurry getting ready for work but now it’s all I can think about!