I completely understand. I’m a lawyer and I frequently need to talk in social and professional settings. The BEST thing for me to get over my fear of blocks is to practice. Just talk as much as you can. Call restaurants and ask what time they close, rehearse speeches to yourself in the mirror. I find that the more I practice, the more fluent I am. I also stay calm and keep my jaw and lips as relaxed as I can. If I don’t think about stuttering or if I’m totally relaxed, I’m completely fluent. If I focus on my stuttering or I’m emotionally keyed up, I lose fluency. It’s an ongoing exercise, but my fluency has improved by leaps and bounds and allows me to be successful in my chosen field. Also, pep talks to yourself help! You have to lie to yourself and fake confidence until it feels natural.