Cool, thanks for the replies!! The thing is, I saw this in the 70's so I think Nausicaa and Castle in the Sky are out of the running because they were made in the 80's.
I wish I remembered more details like names but it's been like 25 years! All I know is that it was a really bleak story, they really played up how lonely the little boy was and how thrilled he was when he finally met another living person.