Mumofsix.... I think calling the doctor would be the best bet in this situation. I do remember after my ET the doctor did say that there would most likely be some cramping, and that sometimes this is accompanied by some bleeding, but only small amounts. I guess it depends on how much blood. If you are going through pads you really should give your nurse a call. They usually give you an after hours number.
I did have a small amount of blood, but it was on day 2 after ET and it was more of a pink colour then red.
Good luck, I hope it all works out ok for you