I agree with Kellie that you matter.
When you share the joys you experience, whether it is a walk with your boyfriend out in nature, or even simpler things like supporting others who are struggling, those are important and not something everyone can do. And yet, you are a natural at it.
The questions you pose, in my opinion, are quite normal and indicate someone seeking a connection. A connection to life, purpose, and perhaps even spirituality. I have felt like that at various times throughout my life because the standard answers I got from "religion" did not make sense to me; they did not answer the fundamental questions I had.
It took decades of research and actively seeking those answers. Then I met someone who took the time to show me the answer to one of my questions. That pointed me toward more answers. And then one day, I was reading an old book, and suddenly it all clicked into place. Everything made sense in a way that nothing before it had.
I hope you will find your way and realize, as we do, that your existence matters. That you do make a difference. Your life journey is important to you and to others you connect with. I don't have an answer for where to look, and it would be difficult to pin down until you find a path you truly enjoy. Such seeking is a personal journey and not one that can be shouted from a pulpit.
When you feel like this, how does your music fit in? Do you feel that you have lost interest in that? You were working on composition, vocals, and lyrics for new projects. Have those been set aside? I ask because if it still holds your attention when you feel like this, that could be a sign pointing you in the direction you need to go to get out of that feeling.
You and I know this feeling is temporary. You have felt this before, and you made it through. You know the way out. I think that now you are just looking for a cause that you can remedy. You will find it. I have no doubts.