I dont think they test LH on day 1? I am supprised they didnt advise you that you probably shouldnt TTC whilst on an IVF Cycle? They shouldnt have left it up to you to find out! Maybe it isnt that much of a concern for them. Perhaps if you are worried, just give them a call. But i really wouldnt worry yourself too much, you are probably under enough stress ATM. The chances that you have fallen preg would be really slim hey. Believe me, I worried about all sorts of things too when undergoing an IVF cycle.
And i know this is a little different, but if it makes you feel any better, my friend fell preg on the pill, and continued it for months before she realised she was even preg!! And i assure you, this didnt harm her child at all.
Good luck with it all. I hope you conceive your little miracle very soon