My 16 month old son wont eat?

he is 16 months old and weighs 17lb, the health visitor says he okay and will not give me any help and i usually leave the clinic crying. i have tried making everything, tried leaving finger foods around, tried baby food and he is not interested. He has just got his 1st tooth and we thought he maybe wasnt eating as he was late getting his teeth but now he has a tooth its just made his eating worse. In a normal day he eats, 1 rusk mixed with water, 2 beakers of water, half a slice of toast, bottle of milk at night. I just think it is not enough. But he is the most active little boy ive ever seen he is always climbing and running and is generally very happy. Am i worrying for no reason? he also sleeps from 7pm to 8.30am.