I'm puzzled...

For the past week almost Kera has been exhibiting some strange illness/vomiting issues. It started last Tuesday. In the middle of the night Kera threw up in her bed. In the morning she came into my room and said there was "red stuff" on her bed. I go in there to see a very unpleasant site. She had thrown up all over her bed and it had all dried up. (Sorry for the graphic image). I found it a little odd that she had done that. But she seemed just fine that morning. So after washing all of her bedding, I kept a close eye on her throughout the day. No strange behavior from her. She was fine for another whole day, so I think it's just a fluke. But sure enough, she wakes me up Thursday morning and says her tummy hurts. It's about 5 a.m. at this time. So I take her into the bathroom where she throws up. I put her back in bed, and she's still saying her tummy hurts, and then she has to go potty(diarrhea). Okay, so finally I get her to go back to sleep. Later when she wakes up she's fine. By fine I mean bouncing around acting as if she had never felt sick at all. So the rest of the day goes smoothly (although a few more loose stool episodes.) Then Friday morning she's fine and is doing well again until she wakes up Saturday morning saying her tummy hurts once again. She proceeds to throw up again (it's about 5 a.m. this time too). She throws up again a few minutes later. Then she goes back to sleep and when she wakes up around 10 a.m., fine. No problems. The whole day she's great, and Sunday is fine all day. Monday goes smoothly, no real problems, just some mild diarrhea. Then this morning she comes into my room about 6 a.m. and says her tummy hurts again. I'm thinking no way can she be doing this again. It seemed like this was over with. But nope, she goes to the bathroom and throws up. I go put her back in bed and when she woke up later that morning, guess what? Just fine. She's been fine all day long. So I'm just waiting to see what tomorrow morning brings, or doesn't bring. I don't know. I'm really stumped on this one. Nobody else in our family has gotten sick. I can't figure out what could be wrong. If any of you out there may have any ideas or have ever experienced this before, let me know! I'm taking her to the doctor tomorrow to see if they can figure it out. I'll post an update after she sees the doctor, if there's anything they can tell me.