Too much alcohol

Late last year we had a big party and we got smashed as they say. I awoke in bed with my sister Carol and we were both naked and I could remember fucking someone, but it wasn't clear to me who. I'm Brian 28 single and I live with my sister Carol 32 divorced, we both like to party and had a partied hard the day and night before. I walked about the house looking for another woman in the place and only found the whole was a mess. Everybody else had left and it was only me and Carol left. It was then I remember that I had locked after the last person had gone and then had another drink and a dance with Carol and the next thing I remember was having sex in bed. With that patchy memory I concluded I had fucked my sister. I made coffee and sat drinking it thinking of the night before trying to remember what happen with certainty. But couldn't really fill in all the parts for certain and hour or so Carol awoke and so I asked her had we had sex, she was shocked at first. She saying you think we had sex last night, I told I could remember having sex with someone and when I awoke this morning I was in bed with you both naked. She thought a while, then said I also remember having sex and can't exactly remember with whom. But I also remember giving him a big love bite on his thigh. I lowered my shorts and showed her a love bite on my thigh. That proved I fucked my sister, no problem. Well yeah she later found she wasn't protected as she had used her diaphragm as she could take the pill it upset her. So we sat and talked about what we had done, I tried to ease the problem by saying I had ready liked the sex and there was just as much of a chance she wouldn't get pregnant. You just put the jinx on me and I will get pregnant she said, jinx or not she got pregnant and the baby is due in the next couple of weeks. On the bright side she lets me fuck her while is pregnant, starting after it was confirmed.