need advice PLEASE!

I started glow a month ago along with stopping my BC pills...then I downloaded Glow as I entered my period for June which was the 29th through July 3rd it placed my fertile window on the 9th through the 15th and my ovulation day on the 12th so we BD on the 12th & 16th (should've been more but our work schedule is crazy) so my AF is supposed to come today the 24th and there is no sign of it so then I decided to go back and enter my period's for March and April so then Glow changed my AF day to start on Friday the 28th from the 24th which is today and it also changed my ovulation day to the 14th im currently on CD 26 early last week I had 2 days where I seen one tiny drop of pink coloring on my pantyliner and on one of those days when I wiped it was just pink kinda weird being since I've never. experienced that so just from reading other stories on Glow im thinking it was implantation bleeding and only symptoms I have are lower back pain a little, no headaches ,nauseous today, around the time I seen the pink I cramped around my left side for a few days I always have brown stuff on tp when I wipe about a week before my AF shows but not this time...when should I test? Does it seem I could be pregnant? Just don't wanna be let down AGAIN!