Developing later

How accurate are pink dye tests that continue to develop after the "time frame" with FMU I saw something immediately, then it kind of went away, then came back and continued to come back stronger afterward. I woke up from a nap after taking it this morning and it looks like a definite pink thick line. Should I not even consider it? I keep seeing people say on here pinks take "awhile" to show the positive especially the brand I had. But I just don't know if I should discount what I saw or not. I took some pregmates after my nap which was about 5 hours after I went this morning and they look negative. I just feel confused.