I love Port too but it so does the same to me, Big headache......I went for a Christmas retreat with my family and they had a bottle of sherry and cake for a welcome pressie, know one tried the sherry so I drank it, its strange as I often fancy a glass but more than one glass is always too much and makes me feel quite ill in the morning.....to me, a sherry seems a lovely Christmas drink......as a child, on Christmas Eve, mum would give me a very diluted Port and Lemonade to help me get to sleep, it worked!!!!
I still feel guilty about my Lab eating a fishermans lunch on our walkies around Gartmorn Dam......poor chap!!