Alergic to Watermelon?

This morning started off so well.....but it did not last.  We all got in the car and we heard Viggo start to get sick. He threw up all over.  I felt so bad.  My kids are such troupers. When they throw up they don't cry or scream they just look so confused as to why their little bodies are betraying them.  I thought at first that he may have gotten sick, because David had been sick this week.  But, he showed no symptoms.  He had no fever, diarrhea, and he didn't have those sad eyes he gets when he is not feeling too well.  That's when David said, "I think he is allergic to watermelon."  Then it dawned on me that the past few times he has had watermelon he has spit it up.  How did  I not realize it.  I guess I just thought maybe he was having a little too much.  But David was right he only had a few bites today. I have never heard of a watermelon allergy.  I am going to make an appt. with a pediatrician just in case.  But one for sure way that I know that he is not sick, is because his appetite has not gone away.  Just look at him and his ice cream.  So, glad he is not sick, but sad that he may be allergic to yummy watermelon :(