Chronic dizziness, no problem with ears and muscle coordination, bobble head, weak legs

My son has been having constant dizziness for two weeks now. We took him to his pediatric doctor and he said the ears look good ond so did his muscle coordination. That we didnt need to come back until something else happened because he didnt have enough information to go on. He however feels like his head is like a bobble head and his legs , waist down feel funny or noodley . We had gone to a park with an amusement ride and it made things much worse. Then, it took a couple of days to get better, but never fully went away. Any direction you could possibly give us to go or what this could possibly be would be appreciated.