Am I overreacting ?

I’m from Missouri and my boyfriend lives in SC. His family called me Missouri a year ago. A old co worker of his called me Missouri via text message and I found out because he sent a screen record. (We were talking about old messages they had together) that’s why I got the screen record. He did not correct this man. We been off and on for a year. I’m extremely upset because I have a fucking name and expect people to use it. My boyfriend says I wouldn’t know about it if I was so nosey. I told him I want him to correct him. He says he will if it happens again. Well why would he let someone disrespect me again?? His sister also puts a K in my name and there’s no k in it at all. Basically making fun of my name for having a Y. Am I overreacting? I told him a year ago I didn’t like the fact I was being called nicknames that he set for me to keep his hoes in order. A year later it’s still happening. What do I do? Am I overreacting??