I'm feeling guilty. Was this right?

Well, I was at a party one night. It was just a normal party that my friend hosted at her house. Then, some guy invited a LOT more guys over and the party got out of control. There was also alcohol that some guy brought in. It was really crazy and out of control, so I was about to leave, when this guy came up to me. He looked drunk cuz he was wobbling a little bit. He then came over to me, and grabbed my hand. He said, "Hey. Look at you fine thing!" I said,"Please let go." He then said, "I don't wanna!" And then touched my . I jerked back and told him firmly to stop. And he said no, and touched it again. So I kneed him in his nuts as hard as I could. He fell like a brick and was moaning a lot, and was writhing in pain. I then left the party. Afterwards, the next day, my friend who hosted the party said she got in trouble by her parents once they came home. Also, the dude I kneed, had to go to the hospital and have a testicle removed, and she was serious. I now feel really guilty. Was this right of me or not?