It's my urine. Sorry, TMI, but it's foul.
Now, I've had UTI's before. I know how bad urine can unfortunately smell. But this is on another level.
Has anyone else noticed it? I don't actually have a urine infection either! I've been pregnant a lot (over 7 times now, not that many babies!) and it's always when I get to around 9+ weeks.
My theory is it's a definite pregnancy urine smell. And not just hormones making my sense of smell change.
Disgusting but I smelt it on someone I know who was about 17 weeks pregnant at the time.... I wasn't pregnancy myself. We are quite close and she spoke to me about it! I didn't say I could actually smell it from the loo she'd used 
Has anyone experienced this? I can't really describe the smell but it's hideous