Help with Friend troubles?

okay, well before i had a conversation with my friend hillary. we were disscussing about one girl named carrie, and it came off to me that she really disliked carrie and wanted me to be on her side about it. Later that day i told my best friend mellanie about the conversation i had with hillary, and told mellanie that hillary told me she hated carrie and asked me that if i was on her side. I got carried away and told mellanie that hillary said that carrrie was a horrible person and she hated her blahhblahhblahh. (i kinda went over board) But then, melliane told CARRIE the story that I told her, and carrie confronted hillary about it. Hillary then texed me upset and angry, but i just kept telling every1 that tht was what she said. now im feeling guilty and dont know what to do, cuz i reallyy dont want to admit i lied, and embarres myself. WHAT SHOULD I DO?? BEST ANSWER TEN POINTS