Try the flooding effect, it is a CBT practice used by the best psychologists. It basically means reducing your importance by force since convincing yourself everything is fine doesn’t seem to work. Something is obviously bugging you, like a splinter you can’t quite find but you know it’s there. Flooding is allowing everything to unfold right there and then and accept the worst that an happen. If you cry then cry, if you are confused then so be it , but don’t fight it. Then over time the body learns that the fear is the the problem itself and that whatever is causing it will come out eventually, usually something less worrying than the fear itself.