I get this sometimes, usually while dissociated. When it hits you, you could try staying more connected to the world, some techniques that may be helpful are listed here: https://sanctioned-suicide.net/threads/grounding-techniques.81102/
If it is more of a constant thing, and not something that hits you for a while and then goes away, I would try to find therapy for it. Also, some schools of yoga help you "feel" yourself, maybe you could look into this, too. But I definitely hope this is not what you are describing, because it sounds even more painful than the other option.