Yes, you can say that. Maybe 'not yet found' instead of 'not found yet.'
Or just put 'currently working as X' and then maybe something like '...; interested in Y,' 'exploring Z,' 'my true passion is Q' ... 'Dream job' is more clichéd, but very common if you really know exactly what you want.
'Vocation' or 'calling' is used more for the helping professions, like charity work, religion, counseling, health care, or in artistic work like music or drama. Words like 'seeking' or 'searching' may also fit these personality types, who are often still seeking even at midlife or beyond, and who may have several different passions, successively or simultaneously.
The exact tone depends on a lot of factors, like your age, interests, and the kind of forum it is. If you're younger, a more creative or altruistic type, or in a more casual forum, a little levity will come across better than if you're trying to network in that forum to get a more traditional job such as in business.
Adults who are really easy-going, or who have enough money not to worry about it, might say something with a wink like 'I still don't know what I want to do when I grow up.' That may come across as sympathetic and funny to other free spirits, but as childish and irresponsible to people in business or HR offices.
'Profession' sounds more formal and better quality than 'occupation,' which in turn sounds more serious than just 'job.' White-collar workers have professions, blue-collar workers have jobs. A lifelong profession is a career. But if you're, say, a carpenter or a gardener and you take your craft very seriously, you can certainly call it your profession, and probably should.
Not sure if that answers your question, but good luck. (-: