Ikigai

To understand the Japanese language, you should learn Japanese culture. Otherwise, you'll come across terms and concepts, which will throw you off.

One important concept of Japanese culture, is Ikigai (生き甲斐). This term built from two words: iki (生き) meaning: life, and kai (甲斐) sequentially voiced as gai, meaning: effect, result, worth.
Consequently, the meaning of the term is "a reason for being". In Okinawa prefecture, the Ikigay thought to be "a reason to wake up in the morning". In western terms it will sound more like "the purpose of life".
Strangely, western people are trying to find the reason for their lives as an universal meaning for life. It gives the impression that all human beings have the same purpose. Personally, I think the universal meaning is not relevant in terms of human short lives. And there is no planned destiny for anyone. Every person should choose his/her reason for being, and this responsibility for his/her own personal life is too much for some people. Generally, a responsibility for anything is a hard thing for many people, but it's a different discussion.
The finding of Ikigay may be not a simple task for some people. Where you should start when you look for purpose? Some do meditation and wait for the enlightenment to come. Others traveling to India or other countries in a belief that all the answers there somewhere, just waiting or them. There are also people who ask others about their purpose in life. Subconsciously they want to draw ideas from others and maybe apply them on themselves. All those ways are legitimate but their effectiveness similar to firing in the dark and hoping to accidentally make a score.
I think there is a better way. Deduce the Ikigay from carefully selected questions.

What I love?
What I'm good at?
What I can be paid for?
What the world needs?

You can use those questions in two ways:

Find your Ikigay
You are open to the world and still didn't decide what you want to do with your life. Great, that's the section for you.

• Firstly, make a list of things that you love doing. It can include anything from painting and reading books, to making research in quantum physics.
• Pick from the list the things you are good at or the things you think you can become good at. 
• For each item you picked, write an estimation of time to become so good in it, that people will agree to pay you for doing it. For example: 3  years to become good pianist or 1.5 years to learn Japanese.
• Think if the invested time will be worth it. Are you ready to do it? What additional elements will you need (money, change of environment, tools for crafting etc.)?
• Now, only one question had left. For each item ask yourself if the action, made by you, will change the world. It may sound big, but you don't have to make a revolution. Maybe some actions will make people more educated, or the oceans will be cleaner, or the technology will become more affordable. There is no limit to the ways you can contribute to the world. Just find a purpose in every action in your list.
• Now it's time to choose from what had left in your list. Have nothing left? Think harder in the previous steps, try to be creative, experiment with topics which interest you and may become your new passion. Good luck. 

Determine the missing part
You already have an occupation, but do you have an Ikigay? Look at the chart below and ask yourself if there is anything went missing from your life. If yes, try to find a way to make it complete. You don't have to switch your life 180 degrees. Maybe little changes or additions will compensate for the missing part. A hobby can compensate for lack of things you love. A volunteering mission can fill the part of contributing to the world. Etc.
And don't forget, you have only one life, so make the most of it. Good luck.