I know exactly what you mean, but you have to stop rehearsing before approaching anyone. It is just making your anxiety worse. I used to do that, heck,I was even afraid. My heart used to beat so hard and fast as I was closing the distance between me and the shopkeeper. Its difficult to not think about it, and it takes courage to just go for it, without preparing. But that is the only way you will ever get over it. I still stammer, but i dont rehearse anymore. Past experiences can haunt you sometimes, I know. But this is how it is,Also, one tip from me would be to always walk into a room like you own it. It has helped me, lmao. cheers!