Any similar experiences?

Lee • Mommy to 3 year old girl! Baby #2 joining us March 2016!!!
On Tuesday I started spotting. I had a Dr appt that day. The heart rate was low (98) and the baby only measured 6w1d. Which would have ment I got a positive preg test at 2w5d (which seems too early so I think the baby is measuring small). I'm not having any pregnancy symptoms. The Dr said I'm at increased chance for miscarriage and didn't do any blood work because they don't think I'll carry the baby that long.
The spotting is red and has had some small clots. Its not getting on my pad - - I just see it when I wipe. It seems to get a little more each day but I still wouldn't describe it as heavy. I'm not really having any cramps. Did anyone else have a miscarriage that started like this? How long did it take to really start bleeding?