Hi, Welcome To HCM & Thanks For Asking Your Query Here you had unprotected sex just one day after your periods ended and also took i pill so chances of pregnancy is absolutely less or nil in this case ,and it is too early to do a pregnancy test your symptoms are most probably related to the emergency contraceptive pill u have taken as these emergency pills have more side effects than regular Birth control pills you can take over the counter pain medications like ibuprofen to relieve pain and avoid heavy meals and taking small meals and drinking plenty of water and fresh fruit juices will help you but If u continue to experience these side effects then u can always consult with ur dr for further assistant I hope it helps Thanks & Get well Soon