Clear blue digital

Aly • Married & a mama to both 💗💙| 2 babes & 2 angel babies in heaven👼🏻👼🏻 2nd baby girl due January 💕

So I am 8 days late, been TTC since New Years. I just took a clear blue digital and it popped up as “pregnant” for a solid two minutes then changed to “not pregnant” suddenly. Was this an invalid test? Should I test again in the morning?