Disappearing lines??

My last period was September 19th, had some heavy spotting around October 11th. I️ feel like I’m pregnant, but I’ve taken 5 tests all on different days, all fmu, all negative, except today’s... today I️ watched as the dye went across the first response test, and when I️t went across I️t showed a faint positive for about a minute, and then I️t disappeared. What does a disappearing positive mean? I️t was a pink test line, not white... help!