How do you stay calm when callers keep interrupting?

This is my biggest struggle. You can scream at me all day and I’m fine with that, i won’t blink at eye. However, if I’m trying to explain something and I’ve only said three words before you start interrupting, it takes every fiber of my being to not lose it and cuss that person out. Then they get mad at you because “you aren’t explaining it.” Ma’am, I’ve barely said three words, OF COURSE I DIDNT, LET ME ACTUALLY EXPLAIN.

I actually enjoy my job but this is my Achilles heel. Do you have any tips?