Yep... anxiety and OCD will do this to you. While it’s very uncommon for you to develop a stutter in your adult years it’s possible. It’s usually by dint of brain trauma but accompanying disorders may cause you to develop a stutter as well. Pretty much everyone here has an anxiety disorder and those who think they don’t have it probably don’t know they have it. You not being able to get a word out is called “blocking.” That’s what happens when your anxiety or fear of judgment inhibits breathe and vocal cord cooperation. I’m really sorry but you need to look at the bright side. You have had years of fluency. use this as a basis of motivation. Also, you need to treat this immediately or it will get significantly worse. It’s also important to note: this is all in your head. Most, if not all of us can speak fluently on our own, away from people. Please please DO NOT let doubt creep in. You have been speaking fluently for years.