Ight guys help me out on this one please?

ok so Im in love with a girl named Danielle but I was on this website one day and this random girl starts talking to me calling me hun so I without thinking about it I called her babe and y and **** and I had no idea she's Danielles best friend but since Danielle loves me hearing this broke her heart n I was shocked I apologized saying I ddnt mean to and stuff but she's all mad and sad and I don't kno what to dO I really do love her but I need help Witt this how do I cheer her up again.. I ddnt even wanna flirt with this other girl so I tried telling her she won't believe me what do I do?