Clairesmummy - you get your surge 12 - 48 hours before you ovulate so the test might have been positive a day or two ago even though you may be ovulating tonight does that make sense
are you temping as you will get a rise as soon as youve ovulated - i like Fertilty friend as it gives you an idea when you did pop your egg with your temps
i hated opks alot and have ditched them this month they drove me crazy!!!!

Ajello id go and get a blood test then youll know for sure :-) i hope your up the duff!

My temps have gone really high
here is my FF friend chart
http://www.fertilityfriend.com/ttc/
what do you guys think - im too scared to test
I hope my temps stay up there