Don't feel bad about it DizzyDi... You're not the 1st and certainly won't be the last.
I'd agree with Flutterby and if possible do a night test to boot provided it's not too long after your tea. If you're likely to eat again before you go to bed that could give you a wee bit more leeway as well. Or just do a few tests over the period to get an idea of which direction your sugars are heading.