Bfn then bfp?!?!

Ashley • 31 yrs old, RN. Wife of 10 years, mommy to our sweet 9 yr old & baby girl born 9-11-16!
I've been testing my Ovidrel trigger out since Sat (6 days post Ovidrel).  Sat +, Sun +, Mon very faint +, Tues -.  Tues was right at 10 days post Ovidrel minus a few hrs.  Tonight I took a test and it was +. 😳 Thought maybe it was wrong, so an hr later took another & it too was +.  What are the chances my negative test last night was a fluke??  I was NOT expecting a +.  Just testing for my own sanity of doing so & curiosity. My 14 day post Ovidrel is Sun @ 330am so that's my official test date.  Anyone have input??  I want to hope I'm getting real + after a - test, but then again not really get excited if Tues was a fluke test. I know I need to wait for Sunday- just curious of opinions.  TIA ladies!