I accidently started a rumour please help :(?

my friend told me she had done it with her boyfriend and i told someone else. now i know this was VERY wrong but i totally trusted this friend NOT to tell and she blatently did and went and told most of the cl. my friend asked me why i had spread it and i told her i hadnt done it intentionally and apologized but she is still pissy about it and half the cl are against me, i was very sorry i did it and said she could get her own back on me but she doesnt want to. i feel so awful about it and im worried about what people will say. i really didnt mean for it to spread :/ what do i do?