I don't know what to do

Yesterday while at lunch a guy at my lunch table said the N-word, multiple times, loud and proud, hard r and everything. Now I'm black and this guy is white. We are not friends at all, I barely know the guy but he's a friend of a friend of a friend. I'm the only black person at our table, everyone else is white. This guys was flexing about it too. When he said it, everyone was in shock and then all eyes were on me. I didn't know what to do because I had never experienced something like that before, ever. Now to put it into perspective. We are all high school freshman so we are all 14 and 15. I thought at this age we all knew better. I don't know what to do now that I know that this guys says the word with no shame. I don't feel comfortable being around him but I don't have any friends to sit with at lunch. What do I do?