I did a HPK this morning with a FR brand. I'm 16DPO (I don't get AF until I stop taking some fertility medication so 16 days isn't significant in itself) and I got a feint line within say 5 - 10 mins. I"ve never had a feint line before. I followed up and did another one about half an hours later and i got a negative.

Is this an evap line? Why would I get a feint line one time and immediately after no line.

I also did a HPK on 14DPO and had no line.

What are your thoughts? Has this happened to you?