Faint line - darker at the top?

j
I am 15 DPO and used a FRER this morning. There MAY have been a very very faint line, but if there was one there, you could see it at the top and then it tapered off. Has anyone else experienced something similar? Husband says he also saw it, but we are both very hopeful so it might be in our heads! 
Plan to test again in a day or two if AF still doesn't show. What are your thoughts?