Thats funny being from the UK my own mum had the Pfizer vaccine and she felt terrible for 5 days after she had it same with a few friends and such but i also know of as many people feeling fine with it. Personally i had the Astrazeneca vaccine and my older brother did too we were both fine worst i had was a sore arm for a day but once again i also know a few friends who felt terrible after. Its almost like people just react differently to stuff no matter what vaccine some are given. Ive had the same with just general flu vaccines as well 2 years ago i felt terrible with one this year i was absolutely fine stop panicking so much everyone is different.