You are pissing me off

I don't know if I am over-sensitive or... it's just him. Being friends with your ex isn't just as easy as it sounds and I definitely do not like the idea of it now because it's so difficult! Everything he said to me is like, he was trying to pick a fight.

"...Whatever, forget it..."
"...End of conversation. Bye..."
"...The food must taste better since it isn't with me..."
etc...

Well, if we were fighting, and he said those words, it's perfectly understandable. But we are at a term that we are just friends, having normal conversation. I don't see how these words can come in. Am I just over-sensitive or... it's just him?