I went to my works Christmas party this week. I joined a bit later than most people so everyone was already very drunk by the time I arrived. I was wearing a low cut wrap dress. One of my male work colleagues who I am friends with came to say hello with another male friend. I was sat down talking to someone and they were stood behind me, while saying hello one of these friends said he couldn't concentrate on what I was saying because he was distracted by my chest and the other colleague agreed. They were being quite leary and one of them grabbed me.under the arms to shake me to tray and make my chest bounce up and down, then the other friend pulled my dress down fully exposing my bra. All of this was in a crowded pub with my work colleagues. I was completely humiliated and immediately told them both to stop but the one who had pulled my dress down wouldn't stop and kept pulling it down despite the fact I kept telling him to stop and he could see I was getting really distressed. Another colleague stepped in and told him.to stop. By this point I was shaking and on the verge of tears. A female.colleague who had seen it then said "they're just tits" and pulled her own top down so it made me feel I was overreacting but I was still upset so decided to.speak to the man who had been doing it and said to him that what he had done was sexual assault and was completely unacceptable. But he just laughed it off and told me not to be ridiculous. I'm a timid person who.hates confrontation so I just decided to leave it but I still can't stop thinking about it now. I don't know if I'm overreacting to be so hung up on it?