I had a girl bred with a repro vet--transcervial. She had dark red spotting for a week after. I called and he said it was nothing. He was right--it was nothing--ultrasound showed no pups.
2 weeks after breeding would be right around the time of implantation. I usually take a little spotting at that time as a good sign that she's pregnant. Obviously it's not a lot of blood - just a few spots here and there.
I agree spotting at 2 weeks is implanting - I have found it sometimes but sometimes not - had litters just fine with spotting at that time although it did scare me the first couple of times!