Boyfriend called me a c**t

Is this okay at all? We were having an argument because I have a problem with not letting arguments go. When he wants to be done I just keep going, I have to be the one with the last word, I just can't control myself. This upset him to the point of calling me a stupid immature c**t multiple times last night and brought me to the point of having a panic attack. I'm seriously upset and offended. He apologized but I don't think it was sincere considering after he helped me through my panic attack he went and sat at his computer for hours to cool off. I want some input here, I don't know if I'm overreacting to this word.