I had some spotting a few weeks ago, I think I was 18 weeks at the time.

Of course I freaked out, but after a couple of days with no more spotting I gradually relaxed and everything is still going fine.

I think these things just happen sometimes.

One thing that can happen is that if you've been DTD, that can break blood vessels on the outside of your cervix and cause a bit of spotting, and that's normal. So that could be the reason and nothing to worry about.