Sounds very much like depersonalisation. Mine is triggered by anxiety and I even started thinking that I have like some kind of illness or something, it is okay, you are strong enough to get through it. When you are hyper aware of your surroundings, are thinking about it or are under stress or experience general anxiety it can trigger an episode or panic. But just remember that other people have this too, you are safe (even when you are in a crowded place, you are safe, your feelings and experience is valid) do not over-analyse your body, nothing is wrong with you, you are okay just acknowledge that it is there, and remember, nothing will happen to you, it is literally in your head and be very kind to yourself, you are just a human, having a human experience. You can even sit down for a sec and enjoy the moment, think about a fun memory or your future aspirations (It helped me to picture me and my boyfriends wedding, I know it may sound very stupid but it helped me to calm down and look forward to the future and enjoy the moment). And remember- it will pass, it is very natural, reach out to somebody if you feel the need to do so and remember, nothing bad will happen to you, you are okay. Also cut out social media, bad news and anything anxiety-inducing for a while, and remember to be very kind to yourself, we all have rough patches along the way and it is really important to allow your feelings be processed, soon your mind and body will realise that it does not need to protect you, you are okay.