My cousin did things to me, what should i do?

ive lived with my auntie and uncle for about 3 months now, they have two sons who livce there too. im 16 and there 17 and 18. on thursday i went out to a party, i came back with a boy, we were both really drunk but just got to 2nd base. he left at around 3 in the morning, i decided to stay on the coach downstairs because i would have made loads of noise going the up the stairs and my auntie and uncle would have killed me. i was watching tv really quietly when jake (my oldest cousin) came downstairs. he could see i was drunk and he told me he saw what had happened between me and that boy. he started feeling my leg, then kissed me, i honestly did try to get away. he wouldnt let me go and started felling me up in places. he went pretty far with me 3rd base. i dont know what to do know, should i say something to someone or just forget about it