I blank out when I’m trying to explain things. HELP.

I have always had difficulty explaining things when I verbally had to do it.

I recently had an interview for another position in my current job with basic questions about the company that I already knew, BUT I started rambling and not making any sense! In my head, I was screaming at myself and telling myself to stop talking, but I couldn’t. The answers weren’t bad, but they weren’t great, making my supervisors think I didn’t know what I was talking about. So, unfortunately, I didn’t get the position, and I knew I wasn’t going to after my interview. But I blame myself now because I knew exactly how to answer every question in my mind, but I couldn’t find the words to express them verbally.

My supervisors talked to me a couple of weeks later about the interview and how it went, and they said they thought I’d perform better than I did. They did say they still wanted to work with me and eventually move me up after proper training on explaining the programs we provide, but I still feel like crap knowing that others got the position and I didn’t. I don’t think I could ever move up if I don’t find a better way to learn how to explain things. This is a small company with about 20 people, and the other individuals who got the position don’t have as much time in this job as I do, making me feel even worse. What can I do to overcome my anxiety with explaining and finding the right words without blanking out?