OPK help

🖤Polly🖤

I’m using the Clearblue advanced and got a low fertility on cycle day 10 then a high fertility on cycle day 11 and I tested this morning (cycle day 12) and got a low again. Anyone had this happen? Did I just get a bad sample/test strip? We’re trying after a mc in October and this is my first cycle. AF was heavier than usual but didn’t last any longer. HPT have been negative.