3yr old vomited excrement?

My 3yr old got over a tummy bug four days ago and I disinfected the whole house afterward. she awoke about an hour or so ago and I put her on the toilet where she had a small amount of diarrhea (Which she has had since the tummy bug) which smelled foul...she went back to bed happy enough and then I was awoken with her crying rather hysterically. I found her throwing up in bed. What troubled me was that it smelled exactly like what had come out of the other end not an hour before, and there were black gskins in it, which she had eaten TWO days ago, and little else. She hasn't eaten much today, but she ate fine the day before and yet none of that was in there. Should I call out a doctor in the morning? Could it be the gs are somehow to blame? If not, how could the tummy bug, which we've all had only come back on her if it's one you can get twice in one week?