Positive then Negative

Erica

Took two one yesterday afternoon after a trip to town, took second one around 2AM! I’m worried I may not be pregnant I have a miscarriage 5/12/18! I want this to be true that I am but why a negative result later?? Please help!! Positive one was first one took in afternoon and negative one was at 2AM last period December 13-17 I’m due to start my period tomorrow