7 weeks old is very young for your kitten to eat dry. Even though he may nibble at it, the bulk fo his food should come in the wet form, 3 to 4 times a day. You can wet the dry to make it easier to eat, also.
His meowing is probably boredom and lonliness. Usually mom and siblings are still around at this age. If a vet says he is healthy than you can leave him alone but try to give many toys and other play items to occupy his mind.