The culture can't wait for you to figure out your occupation. Let it wait. Work on figuring out your vocation. Just like your English teacher told you, check the roots. Occupation comes from the Latin occupare , to take over or possess.
Vocation is from the Latin vocare , a call.
In other words, occupation is something you choose. Vocation chooses you, by name. Occupation is what you take. Vocation is what you give. Occupation is what you do for a living.