Maya vs. Food

When Maya was 6 months and I started her on rice cereal. Well, we TRIED giving her rice cereal.  About an hour after she eats it she gets violently ill. And by violently ill I mean she is full on throwing up every 5 minutes for 5-6 hours. It is worse than any flu bug. She gets all lethargic and she get all gray/pale in color.
I wondered if she just had an allergy to the rice cereal so I tried oatmeal with her. The same thing happened. We also tried peas and carrots and the same thing happens. Any solid food of any sorts seems to do this to her even if she only has 1 bite.
All this has been over the last couple of months and there has been no change. It breaks my heart. We will see what the doctor says about it all.