I wish I could find an old thread on this. It truly depends on how much blood you saw. If it is a little you should be fine. If it was a bunch then you may have reason to worry. I will say that this year I had a cow bleed off like crazy. Swore that she did not stick and she did. If Cowboy is out there he may be able to dig up the old thread that I am referring to. He had excellent points in his explanation of what was happening.
There will often be a bit of blood discharged after a cow has been in heat. Sometimes you see it, sometimes you don't. It says nothing about whether the cow settled or not. I like to see it, as it confirms that she was indeed in heat.