Most of us try to squeeze into the conventional, socially accepted lifestyle because that is the only thing that we know to do. It's the atmosphere in which we are raised--how could we know anything different? And not surprisingly, this produces huge amount of unhappiness for huge amounts of people because the socially defined roles just do not fit most people!
The way to find out what suits you is to simply follow your own intuition and guidance, follow your basic drives and interests. That's tough to do because every move you make, particularly if it really stands out, you'll have your family, friends, co-workers . . . standing on the side with a running commentary. Unfortunate. Yet, if you can negotiate it, you'll find your way to greater happiness and satisfaction in life.
Here are some examples of life purpose that I have come across in giving psychic readings that surprised me and made me gasp at the level of unacceptance from "society," the sort of a thing society would not even give notice whereas from soul perspective the person is not only fulfilling his/her life purpose, but in doing so, is engaged in a noble act.
One is a person coming in not with a specific thing to do in this life for himself, but coming in to support and facilitate others. This person, before incarnation, made agreements with other souls to support them in having certain life experiences, and certain learnings. From an earthly perspective, this may not be such a big deal, afterall, the person is not a great anything, not a writer, leader, mathematician . . . but from the soul perspective . . . oh, my goodness, a nobler act cannot be achieved. The dignity, the nobility, the grandeur of this act is beyond magnificent.
Another socially unaccepted life calling is the person who came in to try everything out and learn from everything. From an earth perspective this person looks like a flake, noncomitted, wishy-washy, never sticking to anything, good at nothing . . . a loser. But that is not at all the case. From a soul perspective, they are doing exactly what they came to do: have as much exposure to as many different life situations and people as possible learning huge amounts in the process.
Anyway, you get the idea. We incarnate here with hugely different purposes--all important and all noble. I'd say, follow closely your own impulses, they lead you to the fulfillment of your soul purpose, no matter how odd it looks from known structures. And be accepting and respectful of others doing the same.