Please hear me out

I always feel lost like I don’t know my purpose or what it is that I want to do with my life. I feel like I want constant change in my life and I don’t want to live a normal life.
I feel like I only truly live in happy interactions with people but I still feel alone in my own world. I don’t know how to explain it but I always get stressed and overwhelmed quickly and easily and can’t let it go. It’s like a pain in my head that spews out sadness.

I’m only 18. It’s so hard for me to find purpose or happiness. I feel like it’s worse than it was years ago and it gets worse as I progress through life.