This girl claims i called her fat when I was talking to my friend, it wasnt to her but she objects. help ?

She is really fat probably why she thought i called ehr but i dont remember why but i called my friend who sits right beside her fat and hes actually skinny. then she stopped talkin to me and a week later i found out when i asked her for a skittle she said not after what u said to me, so i asked my friend who knew what she ment. Then i apologized and said i never said that to her, she said i heard what you said , u said "she" so u its clear who you said it to. But i even told her i wouldnt do such a thing and swore on my own life. but she still doesnt believe me. Now i think everyone of her friends is gonna hate me. Its been really bugging me because i dont like when people see me as an .