Positive OPK - AF is 2 days late....

Laura • Wife and mother to 2 and pregnant with baby #3!
This morning I tested with an opk because I've had a lot of EWCM and AF is late.  I received a very possible result...  The test line is way darker than the reference line.  
​Any insights...?   Seems strange to me since I already ovulated this cycle and AF was suppose to arrive two days ago.