Remember that language is not a fixed science. It evolves naturally and our ways of describing it can change as well.
When I was in school, we didn't have "state of being" verbs. We simply learned that verbs express action or being. The being verbs are also called "linking" verbs because they link together the subject and a predicate adjective. (Ex: "You are frustrated.")
Helping verbs are the little words that accompany the main verb in a sentence, that modify its meaning. You never find helping verbs alone. (Ex: "I will call you." "Will" is the helping verb.)