Solipsism, the uncertainty anyone else exists, is a classic problem in philosophy. See: What are the best Arguments against solipsism?
It sounds like you almost have the inverse problem, a distancing or seperating from your own enacted process of being. That might be related to conceptualising and verbalising everything, and things like mindfulness or Stoic meditations can help us resituate ourselves within our experiences, and shed distracting mental chatter like worrying what others think when that isn't truly relevant. In an age when people can share every activity on social media, there's the risk of putting yourself always in the place of audience, rather than participant, of creating content - never just being content... It is important not just to be a mind, but also to inhabit your body. Athletes have discovered the power of exiting verbal thought to allow the body to work best, which has been called the 'flow state', and that has surprisingly been found to have a lot in common with some types of meditation. Words are great, but they are tools and like all tools they can be used more skillfully if we know how to put them down - otherwise as they say, 'To a hammer everything looks like a nail'.
Existentialist and Absurdist philosophy focuses on how to grapple with our personal experiences of struggling to find meaning, of not feeling 'slotted in' to some big picture we accept (what you might call a metanarrative). I strongly recommend
Existentialism Is a Humanism as a great short accessible text for someone with no experience in philosophy, grappling with the kind of thoughts you are. It's available free online if you look around.
Who you are isn't an idea, a thought. It is being, it is what you do, how you are in the world; which thinking is just a part of. You don't just stumble on to 'finding yourself', you have to make active choices. Philosophy helps us to analyse what it means to live a meaningful and worthwhile life, and so to make firm confident choices how to live. That means doing the work though, reading, articulating own ideas, and developing them through challenge. I think of it as more like growing a plant than making a building, you are collaborating with who you have been and what happened already, you can influence the development, try and listen like a gardener to what is needed next to cultivate yourself, but don't waste time wishing for a different plant.
"we must cultivate our garden.” ― Voltaire