So frustrated !

Malak
So I've been feeling what I think are early pregnancy symptoms for the past week and a half. Two days a go I took a clear blue test and messed it up. 
Today I woke up in middle of night took another clear blue test and got a pretty obvious plus sign ! I know I looked at the test for atleast two minutes. 
I then went to sleep and few hours later woke up and saw that the positive line had disappeared! It shows negative now.
AF is due in a day. 
I don't know what to think. I am tired and frustrated.