I'm thinking you o'd the first drop and the second was a fluke, but I'm no charting expert

Why do you think you used the diaphram wrong? I used one for about a year between Thomas and Lauryn and never had a problem with except leaving it in for the 8 or so hours after bding, especially if we dtd in the morning and I already had the thing in all night. You can't really keep it in for 24 hours
