How is this possible

Nicole • Mom of 4 girls . Trying for baby #5. Hoping for a boy finally . TTC since October 2015.... Last baby was born in June
So I have a uti on antibiotics and all so of course I'm ovulating this time too. Well I took a frer just for the fun of it and this came up within seconds how is this possible and I got a peak just now too on my Opk 
The frer is pink not a different color I thought an indent but within seconds. And got darker pink at 5 mins... I'm on cd11