J.G.
When I had a miscarriage, i had some blood, and then I had a good 8 hours of severe cramps. I soaked super pads every 30 minutes for a good 5 hours.
If this didn't happen, it might be implantation bleeding. This happens with something like 8% of pregnancies. It is associated with a higher risk of miscarriage. In fact, I had it with my miscarriage. But there was no mistaking the difference: with the one, I had a little bleeding, with the other, I was on the couch in pain, bleeding like crazy.
It's good you have a doctors appointment. You could also take a pregnancy test.