Pebbles just to second what brown said. Temporary stresses, even ones that last hours or days, are part of life and don't in my experience prevent conception. I don't even believe prolonged stress does. When DD was conceived I was having a year of chronic stress, so bad that I was having adrenaline sweats at night - if those embies are going to implant, they will!
nanny and brown thank you again for the uplift. Nanny you're right of course, blood tests are the only sure way of getting a reliable answer, but it's so hard to get anything organised at our surgery. If I'm still stumped in a few couple of days' time, though, I will try.
brown your insights are always valuable. Yes, I suppose I have been expecting the FRER line to go from faint to dark in a few days. Still can't shake the feeling that something's wrong, though. The next few days will tell. I can relate to your feeling of moving goalposts! But it does sound as if you have a strong, progressing pregnancy in there. I will be thinking of you tomorrow!