After a night on the town, me and my sister stumbled home drunk. We carried on drinking in my bedroom. After a few more beers she lent over and whispered in my ear how much she wanted me. She then lent in and kissed me quite passionately. One thing led to another and the next thing I knew was that we was passionately making love to each other. After two hours of this we both passed out. I woke up the next morning with very confused feelings for her. Is this normal?