This happens to me multiple times a day, even when I'm relaxed at home.
Frustratingly my children pull me up on it and laugh, my husband never does.
For example, this morning my son put my hair bobble on his head and in my mind I was going to tell him it looked like a crown but I changed my mind and tried to say "it's on your head", but I said "on your KED" because I was thinking of the word crown.
Sometimes I use entirely the wrong word, especially if I feel rushed in the conversation. It's like I can't think of the word and the wrong one blurts out.
I seem to need a lot more processing time than others. It's one of the first skills I lose when really stressed and is why I much prefer using the written word as I can take my time.