Dave, how do we find our purpose?

In 2018. I spoke to an entrepreneur about what I did as a job and so on. She told me this "Take care of yourself first. Help yourself first before you help other people."

The closest to us are the people who can hurt us most. It happened to me. It made me ask myself some days, what's the whole purpose of being useful to help others, when I have nobody to help me in times of need?

How do I change my perspective about this? You have any advice?