It may seem hard to see the purpose, but maybe try to explore your interests. I am really passionate about mental health, tutoring, and helping old people, so I'm planning on developing three organizations based on those concepts that are non-profit. I would say to try and find some volunteer opportunities in your area, explore careers, etc.
A good thing you can try to think about is what is the definition of an ideal person to you based on whatever factors you consider as valuable? When you know what traits you find valuable in an ideal person, those are the traits you want to mimic. Passion really originates from your identity of self: if you say you're a gym freak, you're more likely to go to the gym rather than saying, "I need to lose weight." The same thing goes if you identify as someone who cares about and loves school: if you're thinking about how you have to just get good grades, you might not be as motivated as if you were to make it link to your identity.
Those are just some ideas. I'd also consider watching the TED talk "The Secret of Becoming Mentally Strong | Amy Morin | TEDxOcala" on Youtube because it's a great way to eliminate your negative thinking that undermines any good intentions you have for yourself.