I haven't used one before, picked up a clearblue yesterday and realised should start on certain cycle day. Technically I don't have a regular pattern - anywhere 25-31 days but Flo shows me as 27 days average, based on that I should have started on 5th but I didn't start using til yesterday and got low. Done again today and still low - as per Flo it's saying I should be about to ovulate. Will I have messed it all up by using a few days late? Any help appreciated