Hiya,
I'm in a similar boat at the moment (ie, waiting) though I don't have spotting. I bled for 6 days after MC on 29 April, but after that I've had nothing apart from EWCM the last few days.
Unless you're tracking ovulation then there's no real way of knowing when AF is due (ie, if you can pinpoint ovulation, you'll know that AF's on its way 10-16 days later). I haven't ovulated yet and I'm on CD24. All that we can do is wait, which I agree with you is very annoying!
Regarding the spotting, I would make an appointment with your doctor to help put your mind at rest, rather than worrying about it on your own.